Combine the flour and salt in a food processor. Turn it on, then pour the boiling water in slowly. After each 1/4 cup, pause to check the progress. You have enough when the dough forms a cohesive ball.
Knead the dough on a floured surface for a minute or two, then put in a greased bowl and cover with plastic wrap. Let it rest for an hour or more.
Roll the dough back on the floured surface and make two-inch balls. You will probably have between 10-12 balls, but be sure it's an even number.
Roll a ball and brush sesame oil on top. Sprinkle heavily with scallions, then roll out another ball and put on top of the first.
Roll the stacked pancake out into a 5-inch rectangle, then brush half with more sesame oil and scallions. Fold in half, then roll out again to be roughly 1/4 inch thick.
Repeat with the rest of the dough.
Coat the bottom of a deep skillet with a thick layer of oil. Heat until just smoking, then add the first pancake. Don't crowd the pan; it's fine to do just one at a time. Cook 4-5 minutes, until the side is lightly browned, then flip and cook another 3-5 minutes.
Sprinkle with salt and serve warm. For a crowd, cut into triangles.