Drain both beans separately. Place in separate bowls. With back of fork or hands gently crush beans but not completely.

In medium bowl mix mayonnaise, chives, shallots, mustard lemon, salt and pepper. Separate mayonnaise mixture evenly into two separate bowls. Add white beans to one bowl and black beans to the other bowl, mix gently.

Toast baguette or sliced bread. Place small amounts of basil and watercress equally on each slice. Top greens with one teaspoon of bean mixture to each baguette adding one to two slices of radish, sprinkling lemon zest over top.

Makes approximately 8 of each bean tartines.