The default layout of the RadMap is represented by the UI controls that appear in it. If you want to remove one of them you can easily set the respective property of the RadMap:
Navigation control - NavigationVisibility
Scale control - ScaleVisibility
Command Bar control - CommandBarVisibility
Mouse Location control - MouseLocationIndicatorVisibility
Zoom Bar control - ZoomBarVisibility
In case you want to hide all of the controls and create your own custom layout, you don't have to set each of these properties, you can simply set the UseDefaultLayout property of the RadMap to False.
<telerik:RadMap x:Name="radMap" UseDefaultLayout="False"> </telerik:RadMap>