I am trying to find a way to shell or communicate with GroupWise so that I can open and then send an email to a recipient programatically with C#. I don't have any code, just looking for an api call or a way to shell to get the email open.
It's got a COM automation layer, find it back in your Project + Add Reference, COM tab list. API documentation is here.
Definitely consider using System.Net.Mail.SmtpClient instead.