1) The RadWindow's status bar displays the current url. You can remove it by setting the VisibleStatusBar property to false.But if you want to display the statusbar then, you can use the SetStatus() client-side method and set a custom status string.
2) You can create a custom skin from an already available skin, according to your requirements as described in this help document or you can choose any of the available skins which bests suits your design layout.