This sounds like the sort of thing the Privacy API is designed to take care of - all plugins will be able to report where they are storing data about a particular user so it can be deleted in response to a user's request, and provide a function to perform the deletion.
I'm not sure if the Data Privacy plugin which is being introduced alongside the API will allow users to actually trigger deletion of their own data. From what we were shown at last week's MoodleMoot in Glasgow, it will allow users to request their deletion, and the data protection officer needs to approve it before it's actually triggered.
I suppose something like local_goodbye could be written or modified to do what you're after using the Privacy API, if that's really what you wanted.