Mix flour and 1 teaspoon salt together in a large bowl; pour in boiling water and quickly mix together until water is absorbed.
Work cold water, about 1 tablespoon at a time, into flour mixture just until dough forms.
Knead dough for 10 minutes.
Cover bowl with a damp cloth and let dough rest for 40 minutes.
Turn dough onto a lightly floured work surface; divide into 4 equal pieces.
Roll 1 piece of dough into a large thin round; brush the top with vegetable oil and sprinkle with about ½ teaspoon salt and ¼ the green onions.
Pick up 1 end of the round and roll dough around green onions into a long scroll-shape.
Take 1 scroll end and roll dough into a disk.
Repeat with remaining dough, letting each disk rest for 10 minutes.
Heat about 1 tablespoon vegetable oil in a skillet over medium-low heat.
Place 1 disk on a floured surface and roll into a ½-inch thick round; cook in the hot oil until golden brown, 2 to 3 minutes per side.
Repeat with remaining disks.
