Cut the chicken into bite-sized pieces and marinate with soy sauce and cornstarch for 15 minutes.
Heat oil in a wok and stir-fry the chicken until lightly browned. Remove and set aside.
In the same wok, sauté garlic, ginger, and dried red chilies until fragrant.
Add soy sauce, rice vinegar, brown sugar, and a splash of water to create the sauce.
Return the chicken to the wok and toss until evenly coated.
Stir in roasted peanuts and cook for another 2–3 minutes.
Garnish with sliced green onions and serve hot with steamed rice.