This recipe comes from The Cancer Survivor's Guide from Dr. Neal Barnard at PCRM.
Coarsely mash the beans with a fork or potato masher, leaving some chunks. Add the carrot, celery, green onions, mayo, mustard, salt and pepper.
Place about 1/4 of the mixture on each lettuce leaf. Add one-quarter of the tomato, roll the lettuce around the filling, and serve.
You can add other wonderful ingredients into this salad mix - i.e. chopped avocado, 1/2 tsp pickle relish to create other flavors. Enjoy!