Lone Star, if you are ever near one of the Texas Culver’s, they serve an OK tuna melt with a tomato slice between two slices of sourdough bread. The only problem is that the bread really isn’t crispy enough, but it is still a favorite of mine on their menu. I like the fact that they use mayo. Some places use Miracle Whip, but I think it makes the sandwich too sweet.
I had a crab melt sandwich in San Francisco last year that was wonderful!