Panzanella is a Tuscan chopped salad of bread and tomatoes. This upscale version features halloumi cheese and is super easy because most of the ingredients are grilled, including the cheese.
Preheat grill to medium (350 degrees F to 400 degrees F). Coat zucchini, bread, and halloumi with cooking spray. Place zucchini on oiled (with cooking spray) grates; grill, uncovered, until charred on both sides, 2 to 3 minutes per side. Remove from grill. Place bread and halloumi on oiled (with cooking spray) grates; grill, uncovered, until charred on both sides, 1 to 2 minutes per side. Remove from grill.
Rub both sides of bread slices with 1 of the garlic cloves. (Discard rubbed garlic clove.) Cut zucchini, bread, and halloumi into 1/2-inch cubes. Transfer zucchini and bread to a large bowl; add lettuce and beans. Set halloumi aside.
Place oil, vinegar, salt, pepper, and remaining 2 garlic cloves in a food processor; pulse until combined, 1 to 2 times. Add basil; process until mixture is smooth, about 1 minute. Pour over zucchini mixture in bowl; toss to combine. Divide evenly among 6 bowls; top with halloumi.