Marinate the Chicken:
Toss chicken with soy sauce, cornstarch, and sesame oil. Let marinate while you prep the rest.
Make the Sauce:
In a small bowl, whisk together soy sauce, rice vinegar, hoisin sauce, sugar, cornstarch, and water. Set aside.
Cook the Chicken:
Heat 1 tablespoon oil in a large skillet or wok over medium-high heat. Add chicken and stir-fry for 4–5 minutes until browned and cooked through. Remove and set aside.
Sauté Aromatics & Peppers:
In the same pan, add remaining oil. Toss in dried chilies (if using), bell peppers, garlic, and ginger. Stir-fry for 2–3 minutes until fragrant and slightly softened.
Combine:
Return chicken to the pan. Add sauce and stir well to coat. Cook 1–2 minutes until the sauce thickens and becomes glossy.
Add Final Touches:
Stir in peanuts and green onions. Toss everything together and cook 1 more minute.
Serve:
Serve hot with steamed white rice or noodles. Garnish with extra green onions if desired.