In a large bowl, mix flour and salt. Add boiling water and stir, then add cool water. Mix until a shaggy dough forms, then knead on a floured surface until smooth. Let rest for 20 minutes.
Roll the dough into a thin rectangle on a floured surface.
Brush the surface evenly with oil, then sprinkle the chopped scallions evenly over the dough.
Starting from one long side, roll the dough into a tight log.
Cut the log into 6-8 equal portions.
Take each portion and flatten into a pancake about 1/4 inch thick.
Heat vegetable oil in a large skillet over medium heat.
Pan-fry each pancake for 3-4 minutes per side until golden brown and crispy.
Transfer to a paper towel-lined plate and serve immediately.