In a large pot, heat the oil. When the oil is hot, add the green onions, garlic, jalapeno, ginger and a pinch of crushed red pepper. Stir-fry for 30 seconds. Add the stock and sake. Season with salt and pepper. Bring the liquid to a boil and add the clams. Reduce to a simmer and cover the pot. Simmer for about 8 minutes, shaking the pan occasionally, or until the clams open up. Discard any shells that do not open. Add the pasta and basil. Season with fish sauce. Ladle into individual bowls.