In a bowl, whisk all the ingredients for the spicy honey sesame sauce and set aside.
Drain the tofu from the package and place on a plate. Let sit for 15-20 to remove excess water. Alternatively, wrap the tofu in paper towel or a tea towel to remove excess water. Repeat 3 to 4 times until the tofu is dryer.
In a large pan over high heat, add 3 tablespoon vegetable oil. When the oil is hot, almost smoking, add tofu cubes. Be careful of oil spits! Fry on each side for 2-3 minutes without touching or tossing too much, until golden brown.
Transfer the tofu cubes to a plate covered with paper towel.
Using the same pan, lower the heat to medium and add the remaining 1 tablespoon of vegetable oil. Add the onions and saute for 1 minutes, or until onions are translucent and tender.
Return the tofu cubes to the pan and pour the sauce over. Toss to cover the tofu cubes evenly and cook for 2 minutes.
Turn the heat off, transfer to a shallow bowl and season with salt and pepper if needed. Serve with vegetables and rice.
This spicy honey sesame tofu recipe is best served right out of the pan. If you have leftovers, keep them refrigerated in an airtight container. It will last for up to 2 days.