In a medium size bowl stir together mayonnaise, sour cream, mustard, green onions, capers, celery, dill, parsley, salt and pepper. Gently stir in tuna and white beans.
Spread out 2-3 butter leaf lettuce leaves overlapping each leaf to create a solid surface for the salad. Mound an approximate 1/3 cup of tuna and bean salad onto the center of the lettuce bed. Wrap lettuce around salad, tucking in the ends as you roll, much like a cabbage roll. Cut in half and serve immediately.
Use any white bean that you like here as well as your favourite sprouts or pea shoots for crunch.
Recipe yields a generous 2 cups of tuna and bean salad.