1. Combine first 8 ingredients, and let stand 1 hour.
2. Heat a medium nonstick skillet over medium heat. Coat pan with cooking spray. Add tomato mixture, and cook 10 minutes or until thoroughly heated, stirring occasionally. Remove from heat.
3. Heat a grill pan over medium-high heat. Coat pan with cooking spray. Add bread; cook 2 minutes on each side or until toasted. Rub 1 side of each toast slice with the cut sides of garlic clove halves. Serve tomato mixture over toast.
Heating the tomatoes intensifies their sweetness while preserving their bright, fresh flavor.