In a bowl, combine cornstarch, sherry, salt and pepper. Add chicken and stir to coat, then stir in 1 1/2 t of the oil and let stand for 15 minutes to marinate. Prepare cooking sauce by blending all ingredients in another bowl, set aside. Place a wok or wide frying pan over high heat. When pan is hot, add 2 T of the oil. When oil begins to heat, add garlic, ginger, and black beans. Stir once, then add chicken and stir-fry until chicken is opaque (about 3 minutes). Remove chicken from pan. Add the remaining 1 T oil to pan. When oil is hot, add green pepper, carrot and bamboo shoots. Stir-fry for 30 seconds. Add water and stir-fry for 1 1/2 minutes. Return chicken to pan. Stir cooking sauce, add to pan, and cook, stirring, until sauce bubbles and thickens. If you like food that produces watery eyes and a burning mouth, pass a little bowl of hot pepper & black bean sauce (recipe follows).