Method

Toast dried chillies in a dry pan 30 seconds per side until fragrant. Soak in hot water for 15 minutes until softened. Drain.
About 5 min
Blend soaked chillies, 200g pineapple chunks, ¼ onion, garlic, achiote paste, vinegar, cumin, oregano and salt into a smooth marinade.
About 11 min
Toss pork slices in the marinade. Cover and refrigerate at least 4 hours (overnight is better).
About 11 min
Cook the pork: Heat a cast-iron grill pan or heavy skillet over high heat. Working in batches, grill marinated pork slices 3–4 minutes per side until charred and caramelised. The marinade should form dark edges. Alternatively stack slices on skewers and grill under the broiler, turning and brushing with marinade.
About 11 min
While pork cooks, warm tortillas in a dry pan or directly over a gas flame, turning with tongs, 30 seconds per side.
About 11 min
Chop or shave the cooked pork into small pieces. For each taco, use 2 stacked tortillas. Add pork, a few pineapple cubes, diced onion, cilantro. Squeeze lime juice over the top. Add salsa to taste.
About 3 min

Nutrition per serving (estimate)