Cook the spaghetti in salted water as per the packaging instructions until al dente, drain.
Scrub the clams thoroughly under cold running water. Heat the oil in a wide pan. Sauté the garlic, onion and chilli pepper. Pour in the wine and bring to the boil. Add the clams, cover and sauté for approx. 4 mins. over a high heat, swirling the pan occasionally until the clams open, season. Add the spaghetti and heat gently. Stir in the parsley and oil.