After activating, skip to the "database" tab all the way to the right. Scroll to the bottom and check the box for deleting all the associated tables that WP edit installs. Then click the submit button. That way you'll have a cleaner database in the future.
Then click "Plugins" in your dashboard, scroll down to WP Edit and click "delete." When WordPress asks "Are you sure you wish to delete these files?," click "Yes, delete these files."