WHISK together lemon juice, garlic and 4 tablespoons olive oil until smooth. HEAT grill to medium high heat. Coat bread with remaining 2 tablespoons oil in large bowl. Grill 4 to 5 minutes, turning frequently, until lightly charred on all sides. COMBINE tomatoes, cucumber, bread and mint in large bowl. Toss with dressing. Season with salt and pepper. Top with cheese.