In a medium bowl, mix the soy sauce, sugar, cornstarch, and rice wine. Place the green onion and chicken in the mixture. Allow to marinate at least 15 minutes.
In a wok over medium-high heat, cook and stir the chicken with the marinade mixture about 5 minutes until almost done. Toss in the garlic, onion, and peppers. Continue to cook and stir 5 minutes, or until vegetables are crisp but tender and chicken is no longer pink and juices run clear.
Mix the tofu, water, oyster sauce, and chili paste into the wok. Cook and stir until heated through.