How to Make It
Fill a stockpot with 6 quarts of water, cover and bring to a boil. Add 3 1/2 tablespoons salt to the water and add the linguine. Cover partially just until the water returns to a boil, then uncover, stir the pasta and cook until almost al dente. Drain the linguine, reserving 1/4 cup of the pasta water.
Meanwhile, heat the olive oil in a large nonreactive skillet. Add the onion and garlic and cook over high heat until the garlic is barely golden, about 2 minutes. Add the saffron, red pepper, green tomatoes and their juices and the clams. Cover tightly and cook over moderately low heat until the clams have opened fully, about 7 minutes. Discard any clams that don't open.
Add the linguine to the skillet and cook for 1 minute, tossing well. If the pasta seems dry, add some of the pasta water, 1 tablespoon at a time. Serve immediately.