HEAT OIL OVER HIGH HEAT in a wok or large skillet. Add snow peas, bok choy and shrimp. Stir-fry 3 minutes, or until shrimp are pink. Add salt, pepper, lemon juice, orange juice, orange and lemon rinds, and cook for 2 minutes, covered. Uncover the pan, add the cornstarch mixture, and stir until slightly thickened. Serve immediately. Serves 4.