Alrighty...pop the bread into the toaster. Chop the carrots and celery and put into a bowl with the tuna. Add the chopped cilantro. Next, add in the mayo and the wasabi horseradish. Toss together to combine. Set aside.
Slice half of the avocado into strips, lengthwise. Arrange all the slices of avocado on one of the bread slices.
Spoon the tuna mixture on top of the avocado slices and top with the other piece of toast. Voila!
Recipe by FEASTS AND FOTOS at https://www.feastsandfotos.com/2008/08/28/tuna-fish-sandwich/