Preheat oven to 425 degrees F.
Into a small saucepan over low heat, combine the cornstarch, water, granulated sugar, tamari, apple cider vinegar, garlic, ginger, and ground black pepper.
Simmer, stirring frequently, until sauce thickens.
Into a prepared 8"x8" inch baking dish, arrange chicken-style pieces in an even layer.
Brush generously with the sauce. Then turn pieces over and brush again to coat.
Bake for 30 minutes. Turn and brush with sauce every 10 minutes during cooking.