Recently, I've found another quick way to do that. Do you want to know what's that?
Not long time ago (around 7-8 months), I've posted an article about How to Set Finder Background which teach you how to set custom image as your Finder background replacing the default solid white color.
Note: Don't see the cute icons, see the solid color background..
But, how if you want to set solid color as your Finder background?