Combine cornstarch and soy sauce in a small bowl. Stir to dissolve cornstarch. Blend into chicken broth. Heat oil in a heavy frying pan over medium heat. Add garlic and ginger; stir-fry about 30 seconds. Add vinegar, broth mixture, and sugar.
Stir until sauce thicken, about 12 minutes. Remove from heat; season with pepper to taste. Preheat broiler. Brush some sauce over both sides of the fillets on plates. Sprinkle with chives. Serve with red rice and the remainder of the sauce.