This is deep-fried pork belly on top of a pile of puréed beans enriched with flecks of melted cheese, which can be rolled up into a tortilla so that, depending on when you eat the pork belly, it is either chewy and saturated with bean-y flavor, or still crispy and dry. (See here for an easy way to make crispy pork belly.) I ate a lot of chicharrones burritos growing up, most which came from a little shack on the side of the road with questionable sanitary practices but excellent burritos.
Over the years I've been swapping the chicharrones in the burritos for other deep-fried pork parts: snouts, ears, tail meat, trotter meat, tripe, and pork stomach. The softness of the beans and cheese and the crispiness of the pork is a pretty unbeatable combination, a meal unto itself, especially if you add something vegetal to the mix (green chile being my choice of add-ins, but very soft roasted bell peppers would be nice as well).
That's another benefit you get with the burrito, that it is a completely self-contained unit, which, when it is all wrapped up in its tortilla of a sheath, can be manhandled in a way unavailable to sandwiches and tacos. The beans, no matter how creamy and soft, have nowhere to run. The cheese, no matter how melted, has nowhere to ooze. And you can use whatever cheese and beans you like, all of which makes the burrito an ideal holder of meaty fried bits of meat.