Drain the oil from the canned tuna.
Finely chop the onion and green onion.
Heat cooking oil in a pan and sauté the onion and green onion.
Add the tuna and stir-fry.
Add gochujang, sugar, and soy sauce, and mix well.
Slice the Cheongyang chili peppers and add them, stir-frying quickly.
Once all the ingredients are cooked, transfer to a serving dish.