Cut the tofu, onion, and green onion into bite-sized pieces.
Wrap the tofu with a kitchen towel to remove excess moisture.
Heat oil in a pan and sauté the onion and green onion.
Add the tuna and stir-fry together.
Add the tofu carefully to avoid breaking and stir-fry gently.
Add soy sauce, sugar, chili powder, and minced garlic; mix well.
Once all ingredients are well combined, drizzle with sesame oil to finish.