Cook the pasta according to the package directions.
Meanwhile, in a large saucepan, over medium heat, combine the coconut milk, tomato paste, chili powder, salt, and chili paste or sauce (if using). Bring to a boil. Reduce heat and simmer for 2 to 3 minutes.
Stir in the drained noodles and toss. Divide the noodles among individual bowls. Top with the scallions, sprouts, basil, and coconut.