An aspect of Mexican cuisine I often see neglected in the United States is sandwiches. No, I'm not talking about tacos (and despite what Alton Brown says, I disagree that it is a sandwich, even if it is a similar concept). Though I'm sure there are more, there are three Mexican Sandwiches that I've tried that come to mind:
The torta is probably the most familiar one to us gringos. What's not to love? Grilled meat, cheese, poblanos, chipotle peppers, jalapenos, cilantro, avocado. I'll occasionally see these on a restaurant menu, but they seem to be more common on food trucks, though they're still a rarity this far north of the Rio Grande (Ohio).
Even better than a torta sandwich, in my opinion, is the its close cousin: the cemita. The major difference here is the bread. While a torta typically uses an enclosed white bun, a cemita uses a very rich eggy bread, that shares its name with the sandwich. It's somewhat similar to brioche. While the fillings for both the cemita and torta overlap a lot, I usually see a cemita with a beef or pork milanese (a thin breaded, fried cutlet) rather than grilled or stewed meats like the torta. The other great part about this sandwich is that it almost always comes with quesilla, which is this great string cheese that just brings the sandwich to a whole other level.
Then there is the chanclas. A chili sauce drenched sandwich usually filled with stewed, shredded meat. It is almost similar to enchiladas, or a better comparison might even be the Portuguese Francesinha sandwich.
Something to note here is that all three of these sandwiches seem to originate in the city of Puebla.
I think a big reason we forget about sandwiches in Mexican cuisine is because our mind tends to always focus on the tortilla when it comes to bread. They have great chefs and bakers and a history of baking wheat bread that goes as far back as the Spanish Conquest. It shouldn't be any big shock that things other than traditional native ingredients are becoming more common and are not in any sense any less authentic.