1. Preheat grill to high heat.
2. Divide dough into 4 equal portions. Roll each portion into a 7-inch circle on a floured surface. Place dough on a baking sheet coated with cooking spray and sprinkled with 1 tablespoon cornmeal. Place pizza dough rounds, cornmeal side up, on a grill rack coated with cooking spray. Grill 90 seconds or until blistered. Turn dough; grill 1 minute. Remove from grill. Place zucchini on grill rack coated with cooking spray. Grill 2 minutes on each side. Remove to a cutting board; cut into 1-inch pieces.
3. Combine oil and garlic in a small bowl; brush evenly over top of dough rounds. Sprinkle rounds evenly with Parmigiano-Reggiano. Top with zucchini, onion, and tomatoes, leaving a 1/2-inch border. Arrange anchovies over tomatoes; top with mozzarella cheese.
4. Reduce grill temperature to medium. Carefully return pizzas to grill; grill 4 minutes or until cheese melts and toppings are hot. Remove from grill. Sprinkle with basil, lemon juice, and black pepper before serving.