Thin-sliced pork marinated overnight in a red guajillo-achiote adobo with pineapple juice, seared in thin layers to mimic the caramelized crust of a trompo spit.
1.Toast the guajillo and ancho chiles briefly in a dry pan, then soak in hot water for 15 minutes until softened.
2.Blend the softened chiles with the achiote paste, pineapple juice, vinegar, garlic, cumin, oregano, and salt into a smooth marinade.
3.Coat the thin pork slices in the marinade and refrigerate for at least 4 hours, ideally overnight.
4.Cook the pork in thin layers in a very hot skillet or griddle, without crowding the pan, so it sears and caramelizes rather than steams, about 2-3 minutes per batch.
5.Sear the pineapple chunks in the same pan until caramelized, then fill warm tortillas with the pork, pineapple, onion, and cilantro.