I can't stand it when my kinders touch the walls (especially if another class has some projects displayed & my kids mess with them)
I do this with my kinders everytime we line up to go somewhere (& enforce it the entire way until we get where we're going
Say it like a military drill sargent (sp?):
Teacher says: Facing?
Students respond: Forward!
T: Mouths? (or lips?)
S: Quiet! (or zipped!)
then I can remind the kids what they said before we left ("you told me your arms were crossed so you need to keep them that way")
it works like a charm for me!