Responses with unknown number of fields

I have a situation where I need to read a client’s database schema from an Access database, and then allow them to pick which columns they want to import. I’m writing a service for this which is working fine, except that I currently return the results in a DataTable object, which, as far as I know, cannot be serialized by ServiceStack. I need to return the columns and rows from the database based on the user input to allow them to examine the data. What is the recommended path forward when I’m dealing with an unknown number of fields? I can’t make a POCO, or can I use dynamic? Any help is, as always, much appreciated.

Take a look at OrmLite’s Dynamic Resultset API’s, some of the different API’s was shown in this StackOverflow answer.