In a medium bowl, mix together corn, red onion, jicama, red bell pepper, and cilantro. Stir in lime juice and zest.
In a small bowl, combine cayenne pepper, ground black pepper, and salt.
Brush each fillet with olive oil, and sprinkle with spices to taste.
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.
