The matter described is not somehow related to the Telerik controls.
If you need a Telerik control to open an external page, you can use the RadWindow control. Although you should be aware that in the background the RadWindow renders an Iframe element.
About plain HTML approaches, you can follow these materials:
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.