Tuna Pinwheels

1 (6 1/2 oz.) can tuna, drained and flaked
1/2 c. mayonnaise
1 c. finely chopped celery
2 tbsp. chopped pickle
1 tsp. prepared mustard
20 slices sq. sandwich bread, crusts removed

Combine ingredients (except bread). Roll up mixture in bread slices and secure with a toothpick. Arrange decoratively on a serving dish on a bed of lettuce, if desired. Wrap in plastic wrap and chill until serving.