If you don't have a serrano chile, substitute 1/4 teaspoon crushed red pepper.
Cook noodles according to package directions, omitting salt and fat. Drain; set aside.
While the noodles cook, heat olive oil in a large Dutch oven over medium heat. Add garlic and serrano chile, and sauté for 1 minute. Stir in chicken broth, curry paste, ginger, and coconut milk; bring to a boil.
Add the mussels and clams. Cover, reduce heat, and simmer 5 minutes or until shells open; discard any unopened shells. Remove from heat. Stir in tomatoes, 1/2 cup cilantro, and juice; toss well. Place 1 cup noodles in each of 4 shallow bowls; top each serving with 4 mussels and 4 clams. Drizzle sauce evenly over shellfish; sprinkle each serving with 2 tablespoons cilantro. Serve with lime wedges.