For the time being you can use the following workaround:
CSS:
<style>
html span.RadButton_MetroTouch.rbToggleButton .rbText,
html span.RadButton_BlackMetroTouch.rbToggleButton .rbText {
padding: 0 25px;
}
</style>
ASPX:
<telerik:RadButton ID="telerik:RadButton 1" runat="server" ToggleType="CheckBox" ButtonType="ToggleButton" Skin="MetroTouch"
Text="Click">
</telerik:RadButton>