You can achieve the desired behavior by using the DelegateCommand class (located in Telerik.Windows.Controls assembly). In the ViewModel, you should create a property and variable both of type ICommand. The variable is initialized as an instance of DelegateCommand inside the ViewModel's constructor. In the XAML file you have to bind the Command property, to the property of type ICommand.
Please see the attached sample project, where this approach is demonstrated.