It is possible to read the schema at runtime and get a metadata container out of it. In order to do that you will need to have an OpenAccessConnection (you can obtain one from the context) and do this:
MetadataContainer container =
(DbConnection dbCon = context.Connection)
var reader = DbSchemaReader.Create(dbCon);
container = reader.MetadataContainer;
Unfortunately the serialization to an rlinq file is internal functionality and is not publicly accessible. It is not impossible to access it via reflection however we would strongly advice against that and you should be better off if you write your own serialization procedure.
the Telerik team
Q3'12 SP1 of OpenAccess ORM packs Multi-Table Entities mapping support. Check it out.