I know people can put virus or other dangerous programs in email attachments and send them to you, but is that just for the computer world and not tablets? I mean, if you get such an email to your Gmail account and open it on iPhone for example, is there still a risk of having your information secretly stolen or something?
Theoreticly there's always a certain risk since no system is 100% secure. But given the measures Apple took/takes to make iOS as secure as possible that risk is kept rather low. Currently there is no known security hole regarding what you describe.