Combine meat in a zip-type bag with egg, water, cornstarch and salt; marinate chilled, for at least 30 minutes.
Prep and chill veggies.
Combine water and soy sauce, stir in dissolved cornstarch and rice wine, chill to reserve.
About 20 minutes before serving time (be sure to get rice started) heat about 1-Tbsp of oil in hot wok. Stir meat, drain and discard marinade. Quickly stir-fry the meat in oil, for 60-90 seconds. Transfer to a large container. Stir meat, drain and discard marinade.
Stir-fry the red and yellow peppers until almost tender; add green onions and zucchini, reserve with meat.
Heat the remaining oil and stir-fry garlic, season with pepper flakes and ginger.
Stir the reserved sauce mixture before pouring into seasoned garlic. Heat through to thicken. Sweeten to taste with sugar, adding a bit more ginger and/or red pepper flakes, as needed.