Just something I made. My best friend loves it.
1 can chunk tuna (drained)
2-3 tablespoons mayonnaise
2-4 slices red onion (diced)
1 Golden Delicious or Granny Smith apple (diced)
2-4 slices Cheddar cheese (optional)
Mix tuna, mayonnaise, onion and apple. Spread on bread, add lettuce if desired, top with cheddar cheese. Broil open face and serve.