Toss potatoes with 1 teaspoon oil. Place potatoes on grill rack coated with cooking spray; grill 4 minutes on each side or until tender. Place zucchini, squash, bell peppers, and onion on grill rack; cook 3 minutes on each side. Place bread slices on grill rack; grill 1 minute on each side or until well marked. Rub both sides of each bread slice with cut sides of garlic. Coarsely chop zucchini, squash, and bell peppers. Combine vegetables and Simply Roasted Pork in a large bowl, tossing gently.
Combine vinegar and remaining ingredients, stirring with a whisk. Gradually add remaining 3 1/2 teaspoons oil, stirring with a whisk. Drizzle vinegar mixture over vegetable mixture, tossing to coat. Serve bread with salad.