I´m from Spain, where we don´t use "ándale", but I´ll have a go at trying to translate literally.
Grammatically, the verb "andar" is intransitive in practically every case, which means you couldn't force it to have an object "le", and therefore "'ándale" would be grammatically incorrect.
However, I checked the RAE dictionary, and there is one entry for a transitive use of "andar": http://dle.rae.es/?id=2ZGgAPa|2ZIziL7
Entry 17. tr. recorrer (‖ atravesar un espacio). Andar el camino. Andar todas las calles del pueblo.
So, I would say "ándale" would be an imperative order to "walk it" (where "it" is the path/way, or whatever you have in front of you). Which sort of makes sense as an encouragement to get moving, sort of the correct meaning of it :-) a bit like "go for it"