Add the cornstarch mixed with water to the chicken. Stir until the chicken is lightly coated.
Heat vegetable oil in a large pan over medium heat.
Add the grated ginger and minced garlic to the pan. Cook for about 30 seconds until fragrant.
Add the sliced onion and bell pepper. Stir fry for 2–3 minutes until slightly soft.
Add the chicken to the pan. Cook while stirring for about 5–7 minutes until the chicken is fully cooked and lightly browned.
Taste and add more salt or black pepper if needed.
Add the chopped spring onions and stir for 1 minute.
Turn off the heat and serve hot with rice or noodles.