As far as local data access on these devices, no, Spark was not specifically designed for this.
The data access aspects of Spark are designed to work with SQL Server. If you have SQL Server on the cloud you can wrap a Web API around it -- and Spark will help you building this API. So, when using web services Spark does support WinRT, Phone 8 etc.
I hope this answers your question.
Jack Poorte, Nov 15, 2013