In a small bowl, combine cornstarch, soy sauce, cold water and garlic powder - stir until smooth and set aside. Spray large skillet or wok with canola cooking spray, stir fry the pork strips until no longer pink (about 4 minutes). Add zucchini, mushrooms, onion and green pepper - stir fry for 3 more minutes (periodically coating with additional canola cooking spray). Add set aside mixture to skillet/wok and bring to a boil while stirring for 1-2 minutes or until thickened and bubbly. Serve immediately over hot cooked brown rice.