Cut the chicken and onion into bite-sized pieces.
Heat cooking oil in a pan and stir-fry the chicken over medium heat.
When the chicken is halfway cooked, add the onion and stir-fry together.
Add soy sauce, sugar, minced garlic, pepper, and red pepper powder, and mix well.
Stir-fry until the seasoning is well absorbed into the chicken and onion.
Serve the stir-fried mixture over rice to finish.