Hey, @cerealex.
I know we're talking Catalan sandwich, but it seems like a variation on a pizza—bread instead of dough. My guess is, it's all bread and cheese specific to your part of Spain, though, so the taste would be different perhaps.
Does pantumaca mean something? Is it actually Catalan? I've read about the language but haven't really done much with it. I guess there's over 10 million people who know how to speak it? Amazing!