Whisk together the soy sauce, brown sugar, sesame oil, oyster sauce, rice vinegar, and fresh ginger in a medium bowl until combined. Keep near the stove.
Heat oil in a large frying pan or wok over high heat. Add chicken in two batches and fry until golden on all sides, about 3 minutes. It's okay if it is not cooked through all the way it will continue cooking in the sauce.
Add all the chicken back to the pan along with the red pepper and the sauce. Let the sauce come to a boil for 2 minutes.
Stir in the green onion and sesame seeds and serve with the rice.