Unfortunately, CRM Online doesn't give you direct access to the database layer via SSMS.
There are some good samples in the CRM SDK that show how to retrieve data if you are up for writing some C#. This is their intro sample for how to connect to your CRM instance, gather some data, display it, and then update the entities. http://msdn.microsoft.com/en-us/library/hh675400.aspx
Once you manage to connect to your CRM instance, you will have access to all of your CRM data objects.