In a large bowl combine well the olive oil, the lemon juice, the capers, the cayenne, and the parsley and transfer 1 tablespoon of the mixture to a small bowl. In a large saucepan of boiling salted water cook the fettuccine until it is al dente, drain it well, and in the large bowl toss it with the lemon mixture and salt to taste until the mixture is combined well.
Pat the fillets dry and season them with salt and pepper. In a non-stick skillet heat the vegetable oil over moderately high heat until it is hot but not smoking and in it sauté the fillets, skin sides up, for 4 minutes. Turn the fillets and sauté them for 4 minutes more, or until they are crisp and just flake. Divide the fettuccine between 2 heated plates, top it with the fillets, and drizzle each fillet with half of the remaining 1 tablespoon lemon mixture.
