10 guajillo chiles, seeds removed
3 morita chiles, seeds removed
3 lb. skinless striped bass or halibut fillets, cut crosswise into (1½"-wide) pieces
½ cup fresh orange juice
¼ cup store-bought or homemade achiote paste
5 garlic cloves, 4 whole, 1 finely chopped
¼ cup plus 3 Tbsp. fresh lime juice
1 Tbsp. plus 1½ tsp. kosher salt
½ red onion, finely chopped
1 habanero chile, finely chopped
2 cups finely chopped pineapple (from about ½ medium pineapple)
3 Tbsp. chopped cilantro, plus leaves for serving
Vegetable oil (for grill)
16 corn tortillas
Lime wedges for serving
Bring guajillo and morita chiles and 1½ cups water to a boil in a medium saucepan. Cover, remove from heat, and let sit 30 minutes to allow chiles to soften.
Place fish in a large bowl or baking dish. Transfer chile mixture and soaking liquid to a blender. Add orange juice, achiote paste, 4 garlic cloves, ¼ cup lime juice, and 1 Tbsp. salt and purée until smooth, about 2 minutes. Set aside 1 cup chile sauce, uncovered, at room temperature for serving. Pour remaining sauce over fish and toss to coat. Cover and chill at least 1 hour and up to 3 hours.
Meanwhile, mix onion, habanero chile, pineapple, 3 Tbsp. cilantro, remaining finely chopped garlic clove, 3 Tbsp. lime juice, and 1½ tsp. salt in a medium bowl. Cover salsa and chill until ready to use.
Prepare a grill for medium-high heat; thoroughly clean grate and brush with oil. Working in batches if necessary, grill fish, leaving a few inches of space between each piece, until marinade is dried and beginning to char, about 2 minutes. Using a fish spatula, release fish from grate, turn, and continue to grill until charred on second side and flesh flakes easily with a fork, about 3 minutes more. Transfer to a cutting board and let rest 10 minutes.
Grill tortillas until just beginning to brown in spots, about 30 seconds per side. Top each tortilla with a piece of fish, then a schmear of reserved chile sauce, a spoonful of pineapple salsa, and some cilantro leaves. Serve with lime wedges for squeezing over.