Cut avocados in half and remove the pits. Using a spoon, scoop out a bit of the avocado to make a bigger 'bowl' for the tuna. Keep the excess and add it to the tuna salad.
To make the tuna salad, mix together tuna, excess avocado, mayo (use more or less, depending on how much avocado you add), celery, paprika, salt and pepper. Scoop the salad into the avocados, dividing evenly. Bake for 5 minutes to soften and warm the avocado.
Remove from oven and sprinkle with cheese. Broil for 1-2 minutes until cheese is melty. Sprinkle with chives and serve.
