I see no one answered this, and you probably Googled it, but… iFunBox is available on Mac, too. Beware that the current 1.8 version doesn’t work on Snow Leopard. Some of the UI is powered by internal web browser. As a consequence, the old 1.5 version of iFunBox references web URLs that have since been taken over by malicious content.
When working, iFunBox does let you xfer and manage the content of app document folders, including deletion of document folder contents.