Preheat the oven to 450°. Heat the olive oil in a large, deep ovenproof skillet. Add the chorizo and onion and cook over moderate heat, stirring occasionally, until the onion softens and the chorizo begins to brown, about 5 minutes. Stir in the cayenne. Arrange the clams in the skillet and scatter the tomatoes, garlic and 1/4 cup of the basil on top. Add the wine and roast in the oven, uncovered, for 5 minutes. Stir the clams and roast for about 20 minutes longer, or until most of the clams have opened.
Meanwhile, cook the linguine in a pot of boiling salted water until al dente.
3. Drain the pasta and transfer it to a large serving bowl. Pour the chorizo clam sauce over the linguine, season with salt and pepper and toss to combine. Garnish the linguine with the remaining 1/4 cup of basil and serve.