As a regular Lubuntu user, I really miss one simple thing that Gnome desktop provides out-of-the-box : a right menu on the desktop Trash to allow to directly empty it. Instead, you need to go to PcManFm and then you get a proper menu to empty the Trash !
Hopefully, thanks to latest version of PcManFm, it is now possible to customize some context-menu with your own actions. This means that we are now entitled to create a custom menu specific to the Trash object. This menu will do a simple thing : empty your trash with a dialog confirmation.
This article explains how to add this Empty trash menu to your desktop Trash icon under Lubuntu 14.04 LTS.