For the dough: Whisk the all-purpose and bread flours and salt together in a large bowl. Pour the boiling water over the flour and work it with a spoon and your hands until the water is absorbed and the dough begins to come together. Add 2/3 cup cold water and knead the dough in the bowl until smooth. Cover and refrigerate for at least 30 minutes and up to 6 hours.
For the pancakes: Stir together the peanut oil, sesame oil and some salt and pepper in a small bowl. Puree the kimchee in a food processor.
Divide the dough into 8 equal portions. Sprinkle some flour on a work surface. Working with one portion at a time, roll out the dough with a rolling pin into an even circle about 9 inches in diameter. Brush about 2 teaspoons of the oil mixture over the dough. Sprinkle about 2 tablespoons of the scallions evenly over the surface.
Using a knife or pizza wheel, cut the round into wedges, leaving them attached at the center. Fold the outside edges toward the center until they meet in the middle, creating a rough circle. Roll out the dough again into a 9-inch circle, which will adhere the scallions to the dough.
Cut, fold and roll out the dough again. Brush the top lightly with the oil mixture and sprinkle with a thin layer of sesame seeds. Cut, fold and roll the dough a final time.
Repeat with the remaining dough portions.
Heat a large skillet or griddle over medium heat and brush it lightly with peanut oil. Slide a dough round into the pan. Cook until the bottom begins to brown, about 1 minute, shaking the pan to prevent scorching. Carefully flip the pancake and cook until the bottom begins to brown, about 1 minute. Brush some of the kimchee puree over the surface of the dough and sprinkle with some sesame seeds.
Flip the pancake again. Cook until the dough is set on the bottom, 1 or 2 minutes. Flip the pancake and continue cooking until it is completely set and light golden around the edges, 1 to 2 minutes longer. Brush the top with kimchee puree. Cook the remaining pancakes the same way. Cut into wedges and serve warm.
If making ahead, grill briefly or reheat the pancakes in the oven. Slice into wedges.