Slice the sweet potatoes: Peel (optional) and slice into thin, even rounds about 2–3 mm thick. Rinse briefly in cold water, then pat completely dry.
Mix the batter: In a bowl, combine rice flour, potato starch, salt, and sugar. Add cold water gradually, whisking until smooth and light.
Heat the pan: Pour a thin layer of oil into a nonstick or cast-iron skillet. Heat over medium-high until it shimmers.
Fry the pancakes: Dip each sweet potato slice into the batter and place in the pan. Cook 2–3 minutes per side until golden and crisp.
Drain and season: Transfer to a wire rack or paper towel to drain excess oil. Sprinkle with a pinch of salt while hot.
Make the dipping sauce: In a small bowl, mix soy sauce, rice vinegar, sugar, garlic, sesame seeds, and scallions. Add gochujang for heat.
Serve hot: Arrange the pancakes on a plate, drizzle a little sesame oil if desired, and serve with the dipping sauce.