Beef Cheek Tacos with Árbol Salsa

This recipe comes from chef Traci Des Jardins, who describes it this way: “This has become one of my favorite tacos, and tacos are my favorite food! My maternal grandfather was from near Hermosillo, and we would visit his family regularly when I was a child. On Sundays in Hermosillo, the specialty is tacos de cabeza. This might include lips, tongues, or brains—my favorite— though in my taste memory, the tacos had only the cheeks. I developed this recipe from my memories, making it my own Ca