How to configure outlook to send me Tracking report for my emails - Office 2011 for mac
Here are some instructions on how you can do that. You may also consider using a plugin called sidekick by hubspot. It's a chrome extension that allows you to track emails (not through a program) but I use it with gmail. I don't think it requires permission from the person, which makes it a little less conspicuous.

Let me know if this helps.