Prepare barbecue (medium-high heat). Rub bread with cut garlic halves; brush bread with 3 tablespoons oil. Combine remaining 1/3 cup oil, currant tomatoes, and green onions in medium bowl; toss to coat. Season with salt and pepper.
Overlap tomato slices in concentric circles on platter, alternating colors. Scatter onion and celery slices over tomatoes. Sprinkle with salt and pepper. Spoon tomato and green onion mixture over. Srinkle with crumbled cheese.
Grill bread until golden; about 2 minutes. Cut each slice diagonally in half; serve with salad.