It’s been quite some time since I wanted to do this… I cannot use any other window manager than WindowMaker but with the mini I badly need space on the desktop… I never use the application icons nor the WMClip/WMDock ones… Here is how it all goes away :
First the application icons :

Just right click on the titlebar of your application and launch the specs (attributs in french)… Choose not to have the application icon… Do this again with every application commonly used and you’re ready for the next step…
The WMClip/WMDock icons :

This image speaks for itself… Just open the wmaker preferences and add 2 big red crosses… Restart your wmaker after saving your session…

Now live happily ever after, using alt-1 alt-2… to switch in between desktops…