Hi Daniela! This is kind of a tricky question, and one that assumes that you have something in place that gives users a way to opt in to letting you use their PII in analytics. If you're not, then we're not accountable for any privacy issues you run into :)
If you're using email address to identify unique visitors (as in s.visitorID="daniela@example.com"), you could pull a data warehouse report and use the 'Visitor ID' dimension. If you're passing email into a custom variable, you can simply go to that custom variable's report. If you're not collecting email address in any Analytics variables or dimensions, I'm afraid you're out of luck regarding reporting but in luck in that you don't have to worry about privacy complications.
