A low calorie tuna salad can be twisted and turned in many ways. The classic is the combo of (using fat free or light!) mayo, a dab of mustard, parsley, chopped celery, tomato and onion with a can of light, water packed tuna. White tuna is a bigger fish and contains more undesirables such as mercury. Today since I have left-over fresh green beans, hummus, and cottage cheese, I am placing all that on Romaine lettuce and adding 1/2 can tuna.