The RadMap control does not provide a reader for .tpk files. You can see the supported formats in the Reading Map Shapes
help article. Also, the map's provider works with requests to a service which should return the tile as an image. If you want to use the file locally you can host a service on the localhost and give the file to the custom provider through this service. However, you should convert the .tpk file to images, otherwise the map won't read anything.
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.