A great way to reduce the fat and increase the produce intake of a tuna salad is to:
First, reduce the mayonnaise you usually use by half.
Second, add a few teaspoons of balsamic vinegar.
Third, add diced apples and celery.
Or, leave out the apples and celery and pile sliced avocado on top of the tuna. This pairs so well with the balsamic vinegar.
This makes a fantastic sandwich. I love to eat it from a bowl with toast for lunch.