Step 1

Bring guajillo chiles, chiles de árbol, and 2 cups water to a boil in a medium saucepan over medium-high heat. Cover, remove from heat, and let sit 30 minutes to let chiles soften.

Step 2

Place pork in a large bowl. Purée chiles and soaking liquid, garlic, vinegar, sugar, achiote paste, 3 oz. salt, half of the pineapple, and half of the onion in a blender until smooth, about 2 minutes. Pour over pork, stirring to coat thoroughly. Cover and chill 3–12 hours.

Step 3

If using a gas grill or grill pan, prepare for medium-high heat; if using a charcoal grill, prepare for two zones of heat, medium-high and low. Grill remaining pineapple over medium-high heat, turning once, until charred, 6–8 minutes. Finely chop pineapple and combine with habanero chiles, mint, lime juice, and remaining onion in a small bowl. Season with salt, cover, and chill until ready to use.

Step 4

If using gas grill or grill pan, reduce heat to low; if using charcoal grill, use low-zone heat. Remove pork from marinade and grill until marinade on pork has dried and begins to caramelize and char, about 12 minutes per side. Transfer to a cutting board and let pork rest 10 minutes.

Step 5

Grill tortillas until soft and beginning to char, about 30 seconds per side. Slice pork against the grain into ¼" strips. Top each tortilla with a few pieces of pork and some pineapple salsa. Serve with lime wedges for squeezing over.Do Ahead: Pineapple salsa can be made 4 hours ahead; keep chilled.