01 - In a large mixing bowl, gently combine the cooked rice with soy sauce, mirin if desired, and toasted sesame oil until fully incorporated.
02 - Divide the seasoned rice into 8 equal portions. With damp hands, form each portion into a compact ball or oval shape.
03 - Mix the white and black sesame seeds together in a shallow plate. Arrange flour, beaten eggs, and panko breadcrumbs mixed with the sesame seeds in separate plates for dredging.
04 - Roll each rice ball lightly in flour, dip in beaten eggs, then coat evenly with the panko-sesame mixture.
05 - Pour vegetable oil into a deep frying pan to a depth of 1 inch and heat to 350°F.
06 - Working in batches, fry the rice balls for 2 to 3 minutes per side until golden brown and crisp. Remove with a slotted spoon and drain on paper towels.
07 - Serve warm, garnished with chopped scallions and a sprinkle of shichimi togarashi if desired.