Don't use the e-mail submit button. Use a regular button and set its control type to "submit". On the submit tab, set the URL using the mailto protocol like mailto:foo@bar.com. In submit as, select XML. This will allow users with the free Reader to submit their form data. You will receive an XML data file that you can import into the form using Acrobat.
You say that you don't want the users to save their data. I don't think there's any way that you can prevent that. Also, if they have Acrobat, they will be able to save their completed form.