Thank you for reaching out. You can certainly get a report of all the contacts who opened your email. To access the reports of a specific email, you can click on the actions tab to right of one of your sent emails and then choose the option for "Reports." This will then bring you to a reporting page, showing all your stats. To access the list all of the people who have opened your email, click on the percentage number next to your open rate and the list will load on a new page. Here you also have the option to export the list if you would like too.
Here are some screenshots to help guide you.
Here is also a link to our FAQ on Email Reporting which covers all of the different reports you have access to.