First log into SmarterStats as Admin.

Typically you can access your stats by visiting http://stats.yourdomain.com/ where "yourdomain.com" is replaced with your actual domain name.

You will want to use "Admin" for the Site ID, as well as the username. Your SmarterStats admin password can be found in Unity by going to My Services > My Servers > Server > SmarterStats Traffic Reports.

Once logged into SmarterStats as Admin, Right-Click on whichever domain you wish to view stats for and choose "Impersonate > Site Admin".

This will open a new browser, logging you into the desired site as Admin to view it's stats.