Whisk together orange juice, red pepper flakes, 1 teaspoon olive oil, the garlic and chili powder in small bowl. Pour into gallon-size resealable plastic food-storage bag. Add pork; seal. Refrigerate to marinate for at least 1 hour.
Remove pork from marinade; drain well. Discard marinade. Heat 1 teaspoon oil in nonstick skillet over high heat. Add pork; sauté until cooked, 5 to 7 minutes. Remove pork to plate; cover to keep warm.
Add remaining teaspoon olive oil and onion to large skillet; sauté for 3 minutes. Add zucchini, squash and jalapeño chile. Sprinkle with allspice, salt and pepper. Sauté until squash is just tender, about 5 minutes.
Spoon vegetable mixture and pork into tortillas. Roll up; serve. Makes 4 servings.