The LIB was published just now.
In this latest version, In order to handle a hyperlink when it is clicked, you should attach to AnnotationClicked event of the RadPdfViewer and use something like this:
sender, AnnotationEventArgs e)
Link l = e.Annotation
UriAction a = l.Action
Note that in the future there could be annotations other than Links and Link annotations could have not only UriAction. Also the Action property itself can be null (when the Link annotation is using destination instead).
I hope this helps.
All the best,
the Telerik team