In a small saucepan over low heat, combine the cornstarch, water, sugar, soy sauce, vinegar, garlic, ginger and ground black pepper. Let simmer, stirring frequently, until sauce thickens and bubbles.
[I actually marinated the chicken for a few hours in this sauce before cooking it.]
Preheat oven to 425°F.
Place chicken pieces into a lightly greased 9" x 13" inch baking dish. Brush chicken with the sauce. Turn pieces over, and brush again.
Bake in the preheated oven for 30 minutes. Turn pieces over, and bake for another 30 minutes, until no longer pink and juices run clear. Brush with sauce every 10 minutes during cooking.