Wash potatoes, leave skin on and cut into bite size chunks.
Place in pan and cover with water. Bring to a boil, lower heat and simmer uncovered until potatoes are tender, about 20 minutes.
Drain in colander and sprinkle lightly with cold water.
While potatoes cook, wash celery and onion. Chop celery and mince onion.
Combine onion and celery with the remainder of the ingredients in a large mixing bowl. Drain potatoes well and add to the bowl.
Mix well and refrigerate until ready to use.
Garnish with lettuce and sliced tomatoes.