In a small bowl, whisk together the oyster sauce, soy sauce, sugar, white pepper, rice wine vinegar and sesame oil. Set aside.
In a large, deep skillet or wok, over medium high, heat the vegetable oil until shimmering. Add the chicken and stir fry till lightly browned, 2 or 3 minutes. It should not be completely cooked through yet.
Add the green peppers, onion and fresh ginger. Stir fry till the chicken is cooked through and the onions are translucent, about 5 or 6 minutes.