First make the sauce to give the flavors time to infuse while you make the pancakes.
Combine soy sauce, vinegar, pepper and sugar in a bowl. Whisk to combine. Add scallions and ginger. Stir to combine. Set aside until ready to use.
In a large bowl with the flour, add 1 cup of warm water. Knead to make a stiff dough. Cover with a damp towel and leave to rest for 30 minutes.
In a small bowl, combine the canola and sesame oil and mix to combine.
Divide the dough into four equal portions and roll into balls.
On a well floured surface, roll out one of the balls into a rectangle as thin as possible, approximately 9x12"..
Brush the top with oil. Sprinkle with 1/2 teaspoon of the salt and 1/4 cup of the scallions.Starting at the long end, roll tightly. The dough will elongate as you roll to about 18". Cut into two pieces and roll into a coil. Repeat with the other 3 pieces of dough, cleaning the board with a paper towel before each dough you roll out to remove any oil.
Flour the board well. Take one of the coils and roll into a 8" circle.
Heat a skillet with just enough oil to coat the bottom of the pan.
Add rolled out dough the pan and cook until golden brown on both sides. Repeat until all the dough has been cooked.
Serve with sauce.