In a bowl, place drained tuna, purple onion, and celery.Stir together.
Then add mayonnaise, and lemon juice and mix together with tuna, onion, and celery.
Now add Kalamata olives, roasted red peppers, basil, and capers. Blend these ingredients into the mixture. Taste. Then add salt and pepper.
I use this recipe as an appetizer. I place a spoonful of the mixture onto a thin slice of crusty bread, and a slice of tomato. My husband loves to stuff a tomato with this mixture and have it for lunch.