I use Windows Task Schedular to start up applications when I log into a system. I use this with NDI Screen Capture on most of my systems so I can access them via NDI-KVM.

I don't know if a way to not have the webcam UI pop-up when the application starts, a single click will make it go away. I think what you are really asking for, is to make it so the settings cannot be changed on accident. You can set the NDI Webcam configuration file to read-only to make this happen. The file is called Application.Network.WebCam.v1.json and is located in %localappdata%\NDI