Place zucchini in a 15x10x1-in. baking pan. Toss with 1 tablespoon olive oil. Bake, uncovered, at 400° until tender and lightly browned, 25-30 minutes, stirring halfway. Remove from the oven and cool., Meanwhile, in a large bowl, toss bread cubes with 1 tablespoon olive oil. Transfer to a baking sheet. Bake at 400° until lightly browned, 12-14 minutes, stirring occasionally., Place the cooled zucchini, toasted bread, tomatoes, green pepper and red onion in a large bowl. In a small bowl, whisk together vinegar, garlic, seasonings and remaining oil. Drizzle over salad; toss gently to combine. Add the mozzarella and stir to combine. Serve immediately.