You can't however if you aren't already anonymous I would go change it and then I would disvow it so you basically won't have anything to do with it anymore by clicking on the the image that looks like a broken link that appears under your question before you click on it.
You can't. However, after 24 hours you can disavow the question. This will mean it will not be linked to your account any longer and you will not get notifications from it. Keep in mind once you disavow a question you can't get it back.