1/4 cup millet
1/2 cup cold water
2 1/4 teaspoons kosher salt, plus more as needed
1 medium carrot
1 large red radish
2 tablespoons finely grated, peeled, fresh ginger
1/2 clove garlic, minced
2 tablespoons freshly squeezed lime juice
2 tablespoons mirin (See Cook's Note.)
1/8 teaspoon Asian chili paste, such as Sri Racha sauce
1 pound frozen blanched, peeled edamame (soybeans), thawed
1 1/2 cups panko (Japanese-style bread crumbs)
2 large egg whites, beaten
Vegetable oil, for brushing