Best Ever Tuna Salad

I realize this is a bold claim, but this is by far my favourite tuna salad.  Quick and easy to make this is one of my favourite meals for lunch.

1 can of tuna, packed in water
1/2 granny smith apple, chopped
1/4 cup red onion, diced
1/4 walnut pieces
1 tbsp mayonnaise

Drain the tuna and combine all ingredients.  Serve on any bread you like, if you don't wish to use bread you could have this over a green salad.  Exactly like I said, quick and easy!