1 can tuna
4-5 TBLS mayo of choice
3-4 TBLS shredded cheddar
1 roma tomato
Slice tomato and place slices on small baking sheet. Mix tuna and mayo thoroughly. Place a heaping TBLS of tuna mix on each tomato slice. Sprinkle desired amount of cheese over tuna and top with a bite size piece of avocado. Set toaster oven to toast setting, it will warm up the tuna and melt the cheese. Remaining avocado can be used as garnish on the side.
I'm currently not eating carbs, so this was what I came up with to have a tuna melt for lunch. I hope you enjoy it!