Make the dipping sauce
Mix the scallion, soy sauce, vinegar, sesame oil, sugar, and a pinch of salt in a small bowl and set aside.
Make the pancakes
In a large bowl, mix the all-purpose flour and rice flour with 1 cup of water to make a thick batter. Add the kimchi and scallions and thoroughly mix into the batter. Add the kimchi juice, egg, and salt. The batter should be the consistency of heavy cream, and a light orange color; let it sit for about 10 minutes.
Heat 1 1/2 Tbs. of the canola oil in a 12-inch skillet over medium-high heat. When the surface of the oil begins to ripple or a droplet of batter beads up when added to the skillet, the oil is ready.
For each pancake, add about 1/4 cup of batter to the skillet. Spread the batter with the back of a spoon or ladle to make a thin 3-inch pancake (you can cook 4 at a time). Let the pancakes cook until the bottoms begin to brown, about 2 minutes. Slide a spatula under the pancake and flip it. Flatten the surface of the pancake with the spatula.
Let the pancake cook for another 2 minutes, pressing the surface a few more times. Flip the pancake again, press the surface and cook for another minute. Flip and press one more time, cooking until the pancake is nicely browned on the outside, about 1 minute more.
Set the pancakes on a serving platter and repeat with remaining oil and batter. Serve with the dipping sauce.