Heat a grill to high (450° to 550°). Mix annatto, oregano, paprika, garlic, and 1/4 tsp. each salt and pepper. Rub 1 1/2 tbsp. oil and 2 tbsp. lime juice over steak and sprinkle both sides with spice mixture.
Grill steak, turning once halfway through, 4 minutes total for medium. Let rest 10 minutes. Warm tortillas on the grill, about 45 seconds each, and wrap in foil to keep warm.
Combine jicama, apple, cilantro, and remaining 1/4 tsp. each salt and pepper, 1 1/2 tbsp. oil, and 1/4 cup lime juice in a bowl. Slice steak crosswise. Serve slaw and steak with tortillas.
*Find at well-stocked grocery stores; annatto is also at Latino markets.