Quick Black Bean Salad

1 (15 oz) cans black beans, rinse, drain
1 large tomato, chop
1 (16 oz) package frozen corn
1/2 onion, chop
1 (6 oz) can sliced water chestnuts, rinse, drain
1 bunch cilantro, chop
1/2 lemon or lime, zest
3 TBS balsamic vinegar (or more to taste)

Mix all.  Can be served at room temp or chilled.