gistfile1.cs

public abstract class ViewModelBase : MvxViewModel
{
	protected void ClearStackAndShowViewModel<TViewModel>()
		where TViewModel : ViewModelBase
	{
		var presentationBundle = new MvxBundle(new Dictionary<string, string> { { PresentationBundleFlagKeys.ClearStack, "" } });

		ShowViewModel<TViewModel>(presentationBundle: presentationBundle);
	}
}

gistfile2.cs

public static class PresentationBundleFlagKeys 
{
	public const string ClearStack = "__CLEAR_STACK__";
}

gistfile3.cs

public class SlidingMenuViewPresenter : MvxModalNavSupportTouchViewPresenter
{
	public override void Show(MvxViewModelRequest request)
	{
		if (request.PresentationValues != null)
		{
			if (request.PresentationValues.ContainsKey(PresentationBundleFlagKeys.ClearStack))
			{
				var nextViewController = (UIViewController)ViewCreator.CreateView(request);

				if (MasterNavigationController.TopViewController.GetType() != nextViewController.GetType())
				{
					MasterNavigationController.PopToRootViewController(false);
					MasterNavigationController.PushViewController(nextViewController, false);
				}
	
				return;
			}
		}

		base.Show(request);
	}
}