Clam and Scallion Pancakes (Jogae Pa Jon)

1 cup flour

1/4 cup rice flour

2 egg whites

1 cup water

1/2 cup fresh cherrystone clams, chopped

2 bunches scallions (white parts only), cut into batons

2 tablespoons serrano or green Thai-bird chilies, sliced

1/2 teaspoon salt

2 tablespoons oil

For the Sauce:

1/4 cup soy sauce

1 clove garlic, chopped

2 teaspoons chopped scallion

1 teaspoon toasted sesame seeds

1 teaspoon sesame oil

1 teaspoon vinegar

1/4 teaspoon black pepper