Achiote paste, made from ground achiote seeds, gives fillets of fish a smoky flavor and orange color.
Heat a grill or grill pan coated with olive-oil cooking spray until very hot. Combine the lime juice, achiote paste, oregano, garlic, and black pepper in a bowl; stir until combined.
Spread marinade over each fillet, coating evenly; set aside about 5 minutes. Place fish on grill; cook until flaky and opaque, 6-8 minutes, turning once halfway through cooking. Serve immediately with quick tomato salsa and red-onion and cabbage escabeche.
The 1 teaspoon of achiote paste can be substituted with 3/4 teaspoon chili powder, 1/4 teaspoon cayenne pepper, and 1/4 teaspoon red-wine vinegar.