The easiest way to do that is to remove the page from the Pages collection of the control:
If this does not work for you and you only want to hide the page tab, you can do it as follows.
page.Item.Visibility = Telerik.WinControls.ElementVisibility.Collapsed;
//if you want to hide the page content as well, uncomment this
//if (radPageView1.SelectedPage == page)
// radPageView1.SelectedPage = null;
Note that, even if you hide the tab, the page content will remain visible and if you want to hide it, you need to change the SelectedPage of the control to null or to another page instance.
I hope that you find this information useful.
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Feedback Portal
and vote to affect the priority of the items