1. Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes, just until tender; rinse briefly in cold water and drain. Transfer to a serving bowl.
2. In a skillet over medium-low heat, cook bacon until crisp. Transfer to paper towels to drain; crumble when cool. Reserve 2 tablespoons bacon drippings. Toss 1 tablespoon drippings with pasta.
3. Add tomatoes and lettuce. Stir together mayo, lemon juice, and 1 tablespoon drippings, and add to salad. Just before serving, toss in crumbled bacon and season with salt and pepper to taste.