How to Make It
Preheat the oven to 400°. Toast the walnuts for about 5 minutes, or until fragrant. In a small bowl, beat the egg with the vegetable oil and a large pinch of salt. On a plate, combine the flour with the sweet paprika and 1/2 teaspoon of the hot paprika.
Dip each fish fillet in the beaten egg, letting the excess drip off. Coat the fillets with the seasoned flour and arrange them on a wire rack set over a baking sheet. Refrigerate the fish until the coating has set, about 20 minutes.
Meanwhile, in a blender or food processor, combine the cilantro with the lemon juice, walnuts and the remaining 1/2 teaspoon of hot paprika; pulse to combine. With the machine on, slowly add all but 1 tablespoon of the olive oil and process until blended. Transfer to a bowl and season with salt.
Heat the remaining 1 tablespoon of olive oil in a large skillet. Add the fish and fry over moderately high heat until the coating is crisp and the fish is cooked though, about 3 minutes per side. Transfer to plates and serve with the cilantro-walnut sauce.