"You can launch Microsoft Edge in kiosk mode using the “--kiosk” command line parameter. This opens the browser in full screen with the full screen keyboard shortcut disabled (F11). To accomplish this, create a shortcut with the target set to: "<local path>\msedge.exe" --kiosk http://bing.com"
but the problem is that pressing F11, F12, ESC etc do not work and they don't exit the browser from full screen mode. I've tried now again on latest canary Version 81.0.400.0 (Official build) canary (64-bit)