English Translation
You can’t just ask for the impossible and expect it to be done without any effort.
Here’s another one where the Wiktionary definition is at odds with the sentence or translation.
pedir papas
(idiomatic, colloquial, Galicia) to give up
I see that “pedir la luna” should be a good fit, though.
pedir la luna
loc. verb. coloq. Pedir algo imposible o de muy difícil consecución.