In a small bowl, combine cornstarch and broth until smooth. Stir in the soy sauce, sugar, ginger, garlic powder and pepper flakes; set aside. , In a wok or large skillet, stir-fry pork in 1 tablespoon oil until juices run clear. Remove and keep warm. In the same pan, stir-fry vegetables in remaining oil until crisp-tender. , Stir broth mixture and add to the vegetables. Bring to a boil; cook and stir for 1 minute or until thickened. Return pork to the pan; heat through. Serve with rice and, if desired, sprinkle with cilantro.