Combine flour and salt in a bowl. Pour boiling water in gradually, stirring with a fork. Once cool enough to handle, knead 3–4 minutes until smooth. Cover and rest 30 minutes.
Divide dough into 4 pieces. Roll one piece as thin as possible — about 10–12 inches in diameter. Mix neutral oil with sesame oil and brush over the surface. Sprinkle with salt and scatter scallions evenly. Press gently to adhere.
Roll dough tightly into a cylinder from one edge. Coil the cylinder into a snail shape and tuck the end underneath. Press flat with palm, then roll out again into a 6–7 inch round about 1/4 inch thick. Repeat with remaining pieces.
Heat 1 tablespoon oil in a non-stick or cast iron pan over medium heat. Cook pancake 3–4 minutes on first side until golden-brown. Flip and cook 2–3 more minutes. Press gently for even contact. Repeat with remaining pancakes, adding oil as needed.
Stir together all dipping sauce ingredients. Taste and adjust. Cut pancakes into wedges and serve immediately with dipping sauce.