Cut the chicken drumsticks into 1-inch cubes.
Mix Kung Pao Sauce - Mix ketchup, Chinese black vinegar (or substitute a good balsamic vinegar), soy sauce, sugar, Sichuan pepper oil, cornstarch, and water in a bowl. Set aside.
Heat the skillet over medium heat and place the chicken drumsticks in, skin side down. Don't turn over, about 2 minutes. (Noted 1)
Add garlic and ginger, stir fry for 1 minute.
Cover the pot and simmer for about 2 minutes.
Add the zucchini, and stir for 1 minute.
Add dried chilies and stir for 1 minute more. (Noted 2)
Add the kung pao sauce, cover the pan and bring it to a boil. Before you add it to the pan, stir it well, to dissolve the cornstarch.
Add yellow and red bell peppers and stir for 1 minute.
Add roasted peanuts. Then ready to serve with rice.