Conbini Style Tuna Mayo Onigiri

Name: Conbini Style Tuna Mayo Onigiri
Prep time: 25 min
Total time: 25 min
Cuisine: Japanese
Ingredients: 1 can tuna in oil, well drained; 2 ½ tablespoons kewpie mayonnaise, or regular mayonnaise; ⅛ teaspoon msg (optional); ¼ teaspoon salt (optional); 25 ounces slightly warm or room temperature cooked short grain Japanese rice – about 4 cups (click here to learn how to cook Japanese rice); 4 nori sheets, cut in half

Easy to make, delicious, and kid friendly, onigiri (rice balls) have been a favorite food of mine ever since I was a little girl. This is my version of one of Japan’s most loved snacks – conbini (convenience store) tuna mayonnaise onigiri.

Why I Love This Recipe

Onigiri are not only delicious, they are also very easy to make! This is one of those Japanese recipes anyone can make at home because the ingredients are easy to find and the steps are straightforward. They are also versatile – so many different fillings to choose from aside from tuna mayonnaise – and can be frozen for later. From kids to adults, this popular Japanese snack can be enjoyed on its own or as part of a meal.

Ingredients
Variations
How To Make My Tuna Mayo Onigiri Recipe
Expert Tips
Storage and Reheating
What To Serve With It
Frequently Asked Questions

Ingredients

Rice: For the best rice balls I recommend using short grain Japanese rice because the grains are stickier. Medium grain rice from brands like Kokuho Rose and Nishiki will also work but parts of the rice balls may come apart when holding them, because the grains are less sticky.
Canned tuna: Both canned tuna in water or oil can be used. If you don’t have tuna, flaked salmon or yellowtail is also good.
Kewpie Mayonnaise: Kewpie mayonnaise is the preferred mayonnaise for this recipe because we are replicating the tuna mayo rice balls sold in Japan. Kewpie mayonnaise is fruity, slightly eggy, and packed with umami. It’s much more complex in flavor than regular mayonnaise. However, if you cannot find it, please go ahead and use regular mayonnaise, or check out my recipe for homemade kewpie mayonnaise.
Salt: A pinch of salt is needed to bring the flavors together.
Monosodium glutamate (Msg): Optional but highly recommended. Msg adds depth of flavor and ups the umami level by 10!
Nori: Look for pre sliced nori sheets made for onigiri since they are the perfect size. Otherwise, regular nori sheets will do too.

Variations

Make it spicy: Add a few shakes of ichimi togarashi (red chili pepper) or a squirt of sriracha sauce to add some heat.
Make it vegan: Use plant based tuna and vegan mayonnaise.
Add some crunch: Add one finely chopped celery or a green onion to the filling.
Make it cheesy: This is becoming a popular option in Japan – adding finely chopped cheddar cheese or gouda to the filling.

How To Make My Tuna Mayo Onigiri Recipe

Scroll all the way to the recipe card for the full recipe.

Mix the mayonnaise, seasonings, and canned tuna in a bowl.
Wet your hands and shape the rice balls into triangles.
Press down the middle of each rice ball to create a dent and add a little tuna filling.
Cover the filling with a little rice and finish by wrapping the rice ball with a nori sheet. Enjoy!

Expert Tips

Use an onigiri mold to speed up the process. I cannot live without an onigiri mold since buying one! They are inexpensive and are the perfect size for conbini size rice balls.
Salt the outside of the rice ball for extra flavor. That’s my mother’s trick and one I also like to use. Simply wet the palm of your hands and sprinkle them with salt. When shaping the onigiri, the rice will naturally absorb the salt grains.

Storage and Reheating

Fridge: To save the rice balls for later, avoid wrapping them in nori. Instead, wrap each rice ball in plastic wrap and place them in a storage container. Only use the nori sheet right before eating. They will keep in the fridge for 3 days.

Freezer: To freeze the rice balls, wrap each rice ball individually (without the nori sheet) in plastic wrap and place them in a storage bag or container. They will keep in the freezer for up to 2 months.

Reheating: To warm up the rice balls, take them out of the storage container but keep them wrapped in plastic wrap. Microwave them one at a time for about 30 seconds (up to 1 minute if they are taken out of the freezer).

What To Serve With It

Onigiri can be enjoyed for breakfast, as a mid afternoon snack, as part of a lunch or dinner, or as a late night food. It doesn’t matter when you eat it, there is never a bad time for it! Personally, I like serve onigiri as part of a meal. I make a few of them – 2 or 3 per person – and serve them on a plate along with other snacks and sides.

Some of my favorites are:

Other yummy rice recipes you might like: Spicy tuna roll, pickled plum, okaka, and salmon onigiri, California roll, Philadelphia roll, maki roll, inari sushi, vegetarian kimbap.

Frequently Asked Questions

Can I make rice balls using other types of rice?

The only other type of rice that works to make onigiri is Japanese short grain brown rice. I like to mix 50/50 white rice and brown rice whenever I’m looking to make them a little healthier.

Can I use flavored nori sheets?

I have never tried making onigiri using flavored nori sheets but I think they would be a problem because of their super crispy texture, which would break when folding. If you would like to try, I recommend resting the nori sheets on the rice for a few seconds until they soften, before wrapping them.

Is it better to use freshly cooked rice or can I use day old rice to make onigiri?

It doesn’t matter if you use fresh or day old rice as long as the rice is warm or room temperature. If the rice isn’t fresh it should still be moist and on the warmer side so the rice grains can stick together. But I don’t recommend using rice that’s more than a day old.

Did you like this recipe? Are there changes you made that you would like to share? Share your tips and recommendations in the comments section below!