Currently API does not expose the DMA dimension, so there's no way to access it. Day of week is already available (it's ga:dayOfWeek). BTW, there are no such thing as hidden dimensions in the API. You can view the full list of available dimensions and metrics here.
On Thursday, February 16, 2012 8:39:51 AM UTC-8, Robert Mack wrote:
I am new to GA and need some help with the DMA markets dimension. It
is my understanding that this dimension is hidden but still
available. How do I access this dimension? I am also interested in
the Day of Week dimension. How do I access that hidden dimension?
Please be specific. I would like to use the new version of GA.