Stir the hot water into the flour a little at a time. Some types of flour require more water than others; add only enough to make a lumpy dough. The dough should just hold together when pressed into a ball. Knead the dough on a floured board until it is smooth (3-5 minutes). Put the ball of dough in a bowl and cover it with a damp cloth. Let it rest for at least 30 minutes.
Knead the dough again for 20-30 seconds, just to make sure it is smooth. With your hands, divide the dough into 4 equal pieces. Roll each piece into a ball between your palms, then flatten them into discs. With a rolling-pin, roll one piece of dough into a large pancake about 20-23 cm (8-9 in) across. Sprinkle with a quarter of the salt and chopped spring onions. Roll up the pancake into a long roll, then flatten it with the rolling pin. Roll it into a coil and let it rest for 20 minutes. Do the same with the rest of the dough.
Flatten each coil into a disc and then roll it out again into a large pancake. Dust with flour if the pancake is sticking.
Heat a wok or large frying pan over a high heat until it is hot. Swirl in 1½ tablespoons of oil and, when it is very hot and slightly smoking, turn the heat down to moderate. Pan-fry 1 pancake until it is brown and crispy, flip it over and brown the other side, adding more oil as necessary. Continue with the remaining dough until you have browned them all, keeping the cooked pancakes warm. Cut into segments and serve at once.