Cut the tofu into bite-sized pieces.
Slice the onion and green onion thinly.
Sprinkle a little salt on the tofu and set aside for a while.
Add cooking oil to a pan and fry the tofu on both sides until golden brown.
Remove some oil from the pan and place the onion and green onion on top of the tofu.
Mix soy sauce, minced garlic, red pepper powder, sugar, and water to make a sauce.
Pour the sauce over the tofu and vegetables.
Stir-fry over low heat until the sauce thickens.
Serve on a plate.