In a skillet cook bacon over medium heat until crisp. Reserve 1 tablespoon bacon fat in skillet, drain bacon on paper towels and crumble.
Cut bread into enough 3/4-inch cubes. Heat drippings over medium heat until hot, and saute bread cubes with salt to taste, stirring, until golden brown. Transfer croutons to paper towels to drain and cool.
In a small bowl whisk together garlic, lemon juice, mayonnaise, water, salt and pepper.
In a large bowl toss together onion, tomatoes, cheese, lettuce, half of bacon and croutons and enough dressing to coat. Serve salad and top with remaining croutons and bacon.