Whisk all of the dry ingredients for the batter together. Lightly beat the egg and add it along with the milk, gochujang and scallions to the dry ingredients. Mix until smooth.
Skewer the hot dogs with wooden skewers. Mix the ketchup, gochujang and remaining scallions together for the dipping sauce, set aside. Heat The oil in a tall sided pot to 350 degrees.
Fill a tall drinking glass with the batter, dip the skewered hot dogs into the batter and then place into the oil. Fry each corn dog until the batter is golden brown and the hot dogs are heated through, about 5 minutes. Place the cooked corn dogs on a paper towel lined plate to drain off the excess oil. Make sure to fry no more than 3 corn dogs at time and be careful not to let them stick together.