When i right click on a message and choose 'Move to', i have a list of the recent folders. Is it possible to delete this list ?

you'll want the app to be closed when doing this and of course 1st make a backup

guessing since I don't use Kmail - edit rc file ~/.kde4/share/config/kmail2rc, extrapolationg from an other rc file remove the section [kuick-move]
(or similar) note: file might be ~/.kde/share/config/kmail2rc depending on distro

I have the file ~/.kde4/share/config/kmail2rc but i could nt find there any section about this
There is no kuick move or similar, either 'recent folders' about these folders. (I found recent folders for recently open files)