Stuffed Tomato with Chicken Salad

3  c.     Cooked, chopped chicken
1         6oz. can sliced water chestnuts
1pkg.  slivered almonds (opt.)
1  c.    finely chopped celery
3         green onions, chopped
1  c.    seedless green grapes
1  c.    low-fat salad dressing or mayonnaise
1  T.   lemon juice
6        large tomatoes
          lettuce leaves

Combine chicken, water chestnuts, almonds, celery, grapes, and green onions in bowl.  Mix together salad dressing or mayonnaise with lemon juice.  Mix well into chicken mixture.  On leaves of lettuce, place tomato that has been cut into wedges.  Fill tomato with chicken salad.