What does that mean?
The site you want to show inside the Dashlet requires authentication? You need to establish a session with it?
Is it the same session as SuiteCRM, or a different one?
You probably need some custom code to add that kind of parameters to the URL. But if you can make the site not need the session authentication, that’s easier.
Have a look at this dashlet here, it uses a custom entry-point. That way you can put whatever PHP code you like to make up the dashlet: