Prepare pasta to al dente according to package directions. Drain and rinse under cold water. Drain again. Set aside to cool.
Cook bacon crisp on stove top or in oven, according to package directions. Remove from pan to a paper towel-covered plate to drain.
When bacon is cool to the touch, remove 3 to 4 slices and set aside.
Roughly chop the remaining slices of bacon.
In large bowl, mix together cold pasta, roughly-chopped bacon (See Note below), tomatoes, celery and onion. Mix slightly.
Add salad dressing. Toss well to coat all pieces.
Place several nice lettuce leaves on a serving plate or 1 - 2 leaves on individual serving dishes.
Spoon the salad onto the lettuce leaves.
Finely chopped the 3 - 4 pieces of bacon you set aside in step #3 above. Lightly sprinkle bacon over the top of the salad in the bowl, or on the individual servings. Go easy - don't cover up the beautiful salad too much.
Lightly sprinkle parsley, chives or scallion greens over salad.
Serve cold.