Cold Summer Bean Salad

My little girl asked for it, so here it is.
Cold Summer Bean Salad
1 can 14.5 oz cut green beans
1 can 14.5 oz dark red kidney beans
1 can 14.5 oz garbanzo beans or chick peas
1 cup garlic French dressing
1 medium onion, thinly sliced and separated in rings
Crisp salad greens
Drain beans and peas. Toss with dressing and onion. Chill several hours or overnight, stirring a few times. Just before serving, stir again; drain off excess dressing. Spoon salad onto lettuce-lined plates. Sprinkle with sweet pickle relish, if desired.