I run few days into a problem when I was not able to delete local development storage tables using Windows Azure API and system was throwing me exceptions. The reason of these exceptions I guess was the fact that table were very big.
In basic scenarios resetting can be archived with Storage emulator UI.
I tried this but my machine became unresponsive because due too DSService.exe and sql service.
Killing services left azure tables as they were before.
It turned out that you can also use %Azure SDK%\bin\devstore\dsinit.exe /forceCreate command , which worked perfectly for me.