Make the salsa: Mix the mango, jalapeno, onion, lime juice, cilantro and 1 teaspoon salt in a bowl; fold in the olive oil. Prepare the fish: Mix the instant potatoes, lime zest, cayenne, 2 teaspoons salt and 1/2 teaspoon black pepper in a shallow dish. Beat the eggs in another dish. Season the flour with salt and black pepper in a third dish. Dredge each fish fillet in the seasoned flour, dip in the eggs, then coat completely with the potato mixture.
Place a large nonstick skillet over medium-high heat. Add about 1/2 inch of vegetable oil. When the oil is hot, place the fish curved-side down in the pan; cook until golden brown and crisp, 3 to 4 minutes. Turn and cook until golden on the other side, about 3 more minutes. Top with the salsa and more cilantro.