I made these years ago ... before sliders were called sliders. They were just called mini burgers or sandwiches, etc. We had a friend who often caught fresh tuna on his trips to the FL Keys, and we were lucky enough to get some of it; so I made these as "full size" sandwiches, but for my son and some of our friends kids, made mini sized ones. Everyone loved them so much I started making them "mini" all the time. This really only works with fresh tuna, and honestly never tried it with any canned. But, don't think you need the 2-3" fresh ahi grade tuna for this - some of the frozen or fresh tuna steaks available right in the grocery store work just fine. They are a bit more expensive than a plain burger, however, for a BBQ, dinner party, game night or a special night, these are a lot of fun and very very easy to make. A simple "kicked up" pickled mayo over fresh grilled tuna with fresh baby Bibb or Boston lettuce makes this a simple sandwich to put together. Now you can always add cheese, even sliced tomatoes if you want, but I like it as is. Two secrets ... make sure to use fresh tuna and a good soft whole wheat dinner roll (I got mine right at my local store, doesn't have to be anything special).