Prepare outdoor grill for direct medium-hot grilling. For a gas grill, preheat grill on high. Adjust temperature to 400°F For a charcoal grill, build fire and let burn until coals are covered with white ash. Spread coals and let burn for 15-20 minutes.
Whisk vinegar, 1 teaspoon salt, and hot red pepper together in large bowl. Whisk in oil. Add basil, oregano, and garlic. Add pork loin and toss to coat. Spread zucchini and bell peppers on top of pork, season with remaining ½ teaspoon salt, and let stand 5 minutes. Stir to coat with marinade. Do not marinate longer than 15 minutes. Skewer pork, zucchini, and bell peppers, alternating ingredients, onto 6 metal kabob skewers. If using wood skewers, soak for at least 30 minutes before using.
Lightly oil cooking grate. Place kabobs on grill and cover grill. Cook, turning occasionally, for about 10-12 minutes or until pork is browned. Let stand for 3 minutes, then serve.