Stir together the kimchi, kimchi juice, flour, eggs, and green onion in a bowl.

Heat vegetable oil over medium heat in a large skillet. Using about 1/4 cup of batter for each pancake, pour into skillet, spreading as thin as possible. Cook pancakes until set and lightly browned, turning once, 3 to 5 minutes per side. Season to taste with salt.

Whisk together the rice vinegar, soy sauce, sesame oil, chili pepper flakes, and toasted sesame seeds. Serve with the pancakes.