Sift the flour and salt into a large bowl. Make a well in the center, pour in the eggs and gradually beat them into the flour with a wooden spoon. As the dough gets thicker add the water gradually until you have a soft, just-runny dough.
Bring a large pan of salted water to the boil. Take a small cupful of the soft dough and either rub through a flat Spätzle disk with a flat spatula or rub through a colander with the back of a ladle. The dough will fall into the water as thick "squiggles". They cook very quickly — when they rise to the surface of the water allow them a few seconds longer, then scoop out with a slotted spoon into another colander.
If cooking ahead, then drop the cooked Spätzle in iced water for a couple of minutes. Otherwise, dress with a little melted butter and seasoning.