Stir chicken, onion, garlic,salt, and black pepper together in a bowl until chicken is coated.
Put 2 cup Corn starch in a bowl and dip each chicken piece in the powder to coat it, one by one. Squeeze to press the coating to it tightly.
Put 4 cups of cooking oil in a frying pan. it’s hot enough to start frying. Slide the coated chicken piece one by one into the hot oil and cook for about 1o minutes,
Turn off the heat, and let the sit fried chicken a few minutes.Reheat the oil and fry the wings again for another 12 minutes.
Crushed red chili,garlic vinegar together. Crushed until looks like a fine paste
Heat a large non-stick skillet or wok over medium high heat. Add 2 tablespoons cooking oil and the dried red chili pepper paste.
Add soy sauce,brown sugar and mustard sauce (optional). Stir with a wooden spoon and let it bubble for a few minutes.
Sprinkle some sesame seeds over top and serve immediately.