For oaxacan cuisine expert and restaurateur Iliana de la Vega, weeknight dinners demand sandwich-­style simplicity. One favorite is Chilean lomito, which combines pork, avocado and tomato on a mayo-slathered roll. It’s “the best sandwich in the world,” de la Vega says. To make our version, in a small bowl, stir together 2 teaspoons dried oregano, 1 teaspoon ground cumin, 1 teaspoon kosher salt and 2 teaspoons black pepper. Cut two 1¼-pound pork tenderloins (trimmed of silver skin) in half crosswise, then pound each piece to a ½-inch thickness. Rub the pork with the seasoning mix. In a 12-inch skillet over medium-high, heat 2 tablespoons neutral oil until barely smoking. Add the pork and cook until well browned and the centers reach 135°F, 10 to 15 minutes. Transfer to a platter, tent with foil and let rest for about 10 minutes. In a small bowl, whisk together ½ cup mayonnaise, 1 tablespoon each Dijon and yellow mustard, 1 tablespoon lime juice, ½ teaspoon dried oregano and ½ teaspoon pepper. Roughly mash the flesh of 2 avocados in a bowl with a fork; season with salt and pepper. Thinly slice the pork against the grain, then return to the platter and toss with the juices. Split and toast 6 crusty, soft-crumbed rolls. Spread the mayonnaise mixture on each roll half. Add the avocado to the bottom halves, then top with the pork, tomato slices and upper halves of the rolls.