In a medium bowl add all ingredients for the marinade, stir until cornstarch is dissolved. Add chicken, stir until all pieces are well coated, and let rest for at least 15 minutes.

For a sauce, in a bowl mix all ingredients and set aside.

Heat a wok or a large pan until hot, add oil, peanuts, and red pepper flakes. Stir-fry the peanuts until they start to brown. Transfer to a plate. Reserve the oil in the wok. Add chicken and cook until it starts to brown. Add the red and green bell peppers, zucchini, and then stir-fry until the chicken is mostly cooked.

Stir in the minced garlic and grated ginger and continue stirring for about 1 minute.

Add the sauce and return the peanuts, and continue stir-frying until the sauce thickens.

Transfer to a plate, sprinkle with green onions and serve over rice.