Have people never heard of a tuna melt? This is just a tuna melt. The only crime here is the pineapple. But I guess if you're into that kind of thing it would probably taste good to you.
Usually tomatoes, but I've had them with tomato sauce too. I can't remember if I've had them with black olives, but I should! They're delicious and would totally improve upon a tuna melt.