Prepare the chicken and sesame seeds.
Cut the chicken into bite-sized pieces and chop the onion, green onion, and garlic.
Heat sesame oil in a pan, then sauté the garlic and green onion.
Add the chicken and cook until browned.
Add the onion and stir-fry together.
Season with soy sauce, sugar, and pepper.
Add plenty of sesame seeds and stir-fry once more.
Place in a bowl and sprinkle with sesame seeds to finish.