Bring water with lemon zest to a boil, when boiling remove the zest, add salt and sift flour in beating well.
Beat untill you have no lumps left.
Set aside for about 1 hour.
Heat frying oil.
The recipe I found says to form churros with a sac- a- poche or the specific "churrera" on a floured surface, then to close them in a ring shape.
I only squeezed the dough into the frying oil; dough is not that soft but you can do it without big fuss if you have a good sac- a- poche with a big star nozzle.
When the churros are gold on both sides remove them from oil, drain excess on paper towel, sprinkle with caster sugar and serve immediately with hot, thick chocolate or black coffee.