Hi,
You can do that, by using the "Custom ID" option among the link options.
You would have to put than something like:
mailto:@ID
into the Custom ID textbox. For "Link Column" you will have to select the column with the email addresses.
But from the security point of view this makes only difference to the human visitors to your website. Usually one would care more about the bots that crawl over the internet and collect any kind of data. They would still be able to read the "mailto" addresses.
