1. Preheat oven to 350°.
2. Layer bread on a baking sheet; coat with cooking spray. Bake at 350° for 18 minutes or until toasted.
3. Cook bacon in a large nonstick skillet over medium heat until crisp. Remove bacon from pan, reserving 1 tablespoon drippings in pan. Cut bacon into 1/2-inch pieces. Stir oil into bacon drippings in pan; remove from heat. Stir in vinegar, pepper, and salt.
4. Combine lettuce, tomatoes, and onions in a large bowl; drizzle with vinaigrette. Add bread; toss well to coat. Sprinkle with bacon and cheese. Serve immediately.