Unfortunately, there is no build in support for field/property encryption in Telerik OpenAccess ORM.
Nevertheless you are free to use the existing encryption mechanisms provided by the .net framework to encrypt/decrypt your values, and choose the encryption mechanism that fit your needs.
You can find them here.
Hope that helps.
Do come back if you have any other question.
the Telerik team
Telerik OpenAccess ORM Meets ASP.NET Web API. Read more.