Step 1

Cook macaroni according to package directions; drain and rinse in cold water.

Step 2

In a large bowl, combine the macaroni, green onions, tomato and celery.

Step 3

In a small bowl, combine the mayo, vinegar, salt and pepper. Pour over macaroni mixture and toss to coat.

Step 4

Cover and refrigerate at least 2 hours. Just before serving, add bacon.