Make the orange sauce by mixing soy sauce, vinegar, rice wine, sugar, chili flakes, and orange zest in a bowl.
Cut chicken into bite-sized pieces and marinate in a batter made from flour, cornstarch, salt, and water.
Fry the chicken in vegetable or peanut oil and drain on a wire rack.
Stir-fry broccoli, red peppers, and green onions (optional) in a separate skillet.
Combine the chicken and veggies, pour the orange sauce over everything, and toss to coat.
Serve with jasmine rice or chow mein and garnish with scallions and chili flakes if desired.