Stir together flour, salt, hot water, and 1 tablespoon vegetable oil. Transfer to a lightly floured surface. Knead dough until soft and smooth, 10 minutes. Cover with plastic wrap; let stand 20 minutes.
Roll dough into a 16-inch log on a lightly floured surface. Cut into 24 pieces. Roll each piece out into a 4-inch circle, keeping remaining pieces covered as you work. Brush with sesame oil; sprinkle with 1 teaspoon scallions. Roll each piece into a tight cylinder; pinch ends to seal. Press to flatten. Wrap each cylinder around itself to form a spiral (seam side in); pinch end. Cover with plastic wrap; let stand 20 minutes (or up to 5 hours).
Place spirals on a lightly floured surface. Flatten gently. Roll out to 4-inch circles, stacking between pieces of floured waxed paper. Let stand 20 minutes.
Meanwhile, for dipping sauce, whisk together all ingredients. (Makes about 3/4 cup.)
Heat 1 tablespoon vegetable oil in a 12-inch skillet over medium-high heat. Cook pancakes, 2 or 3 at a time, flipping once, until golden, 2 to 3 minutes per side (add oil as necessary). Drain on paper towels. Season with salt. (To keep warm, place in an oven heated to 200 degrees.) Cut into wedges, and serve with dipping sauce.