How to Make It
Combine salt, paprika, and cayenne in a small bowl. Drizzle fish evenly with 1½ tablespoons of the oil, and season all over with salt mixture, pressing to adhere.
Heat a grill pan over high. Brush grill with ½ tablespoon of the oil. Add fish and cook, turning occasionally, until lightly charred and just cooked through, about 5 minutes. Transfer fish to a plate and tent to keep warm. Brush pan with remaining ½ tablespoon oil. Add scallions and cook, turning occasionally, until lightly charred and tender, 1 to 2 minutes.
Divide fish, scallions, avocado, and pico de gallo among tortillas. Serve with lime wedges.