Presumably he wants XBMC to open Videos > Files on startup.
System > Settings > Appearance > Skin > Startup Window > Videos, appears to be the best it can do. You'd still need to drill down into Files, Playlists or Video Add-ons.
Personally, I set Startup Window to Home window, then create a favorite for the SMB source with my video in it. So to watch video, I launch XBMC > click Menu (on the remote) and click the favorite.