Prepare the sauce by mixing together the orange juice, soy sauce, cornstarch, ginger, and garlic paste. Set aside. Heat 1 tablespoon oil in large skillet or wok. Stir-fry onion, carrots, and mushrooms for 1 minute over high heat. Add squash, broccoli, and snow peas and cook for about 2 minutes. Add remaining vegetables and cook until red pepper is tender. Stir sauce and add to skillet. Simmer until sauce has thickened. Serve immediately over rice or noodles and garnish with orange zest and orange slices.