Grilled Lebanese Salad

Ingredients

• 8 plum tomatoes -
• 1/2 pound whole fresh mushrooms -
• 2 medium red onions -
• 2 medium green peppers -
• 6 tablespoons olive oil, divided -
• 1/2 teaspoon garlic salt -
• 4 cups cubed French bread (3/4-in. cubes) -
• 2 teaspoons dried thyme -
• 1 teaspoon dried oregano -
• 1/2 teaspoon salt -
• 1/2 teaspoon pepper -
• 1 medium cucumber, peeled, seeded and sliced -
• 1/2 cup fresh basil leaves, thinly sliced -
• 3 tablespoons balsamic vinegar -