could someone please explain to me the technique for getting the icing to cover all the cupcakes and be so smooth, do you pipe the icing over all the cupcakes at once then smooth it out?

you can cover cuppcake in buttercream with a disc of fondant on top or use poured liquid fondant that will go flat and shiny

First I attach the CC to the cake board with tiny glue dots that you can get in craft stores. I prefer this to icing on the bottom of the cc as glue because the icing on the bottom of the cc is just a mess waiting to happern I just smooth the buttercream on with a spatula and then VIVA it. Easy peasy.
Did that on this CCC:
http://www.flickr.com/photos/hjscakes/3896527773/in/photostream