Drain one can of chunk light tuna and put into food processor.
Add desired amount of mayonnaise (better to start out with a little then add more as you blend and taste test until you get the hang of it) The more mayo you add, the thinner the mixture will be.
ALLERGY INFO: If you're allergic to dairy and eggs you can get a mayonnaise alternative such as one made from soy. It tastes just as good as mayo sometimes even better.
If bread is tolerated, spread a generous amount of mayo on one or two slices of bread with crust removed and put tuna on top of one slice and eat with a fork or make a traditional sandwich with two slices. Or just eat tuna as is.
ALLERGY INFO: Gluten free bread and mayo alternative can be used instead.
NOTE: Adding things like celery doesn't usually work because it is too stringy and does not puree, but you can experiment with different things to make it more of a tuna "salad"
To add to the flavor you can make a tuna melt by putting one slice of American cheese over the tuna and heat in microwave until cheese has melted.
ALLERGY INFO: A cheese alternative can be used here as well.
A bowl of soup and a healthy drink make this a great lunch. You can buy chunky stype soups and blend them in the blender.