1. Preheat grill for high heat.
2. In a medium bowl, mix together corn, red onion, jicama, red bell pepper, and cilantro.
3. Stir in lime juice and zest.
4. In a small bowl, combine cayenne pepper, ground black pepper, and salt. Brush each fillet with olive oil, and sprinkle with spices.
5. Arrange fillets on grill grate, and cook for 3 minutes per side. For each fiery fish taco, top two corn tortillas with fish, sour cream, and corn salsa.