Drain tuna. Tear lettuce into bite-sized pieces. Core apple and cut into eight wedges. Cut each wedge crosswise into 4 or 5 chunks. Each apple piece will still have peel on one edge. Red apples look especially nice. Combine tuna, lettuce, apple and chopped celery. Add optional ingredients as desired. Add Thousand Island dressing and toss until well blended. Serve with crackers or specialty bread.