Tuna Melt

Saw the tuna melt on the menu at Sweet Mothers Kitchen while in Wellington recently, I was curious, but I got a burrito. With my amazing (ha!) powers of recall I thought to make it for lunch today. One of my few food issues is warm canned tuna, but this was surprisingly tasty. Needs about ~1/4 the mayonnaise and I can't imagine the celery is necessary or essential, Swiss or Emmental cheese probably is.