How to start VNC from display-client?

for reasons not to have to set up port forwardings on each router, to which the Mini PCs with xibo players are connected, I think about a solution to initiate a VNC-connection by the Mini PC to my admin-PC. From behind a router it is easy to make a connection to a VNC host outside.

How would you do that? Would it be possible to install VNC on the client/Mini PC, on which xibo player is running, and to set up a xibo command which starts VNC with a connection to my admin-PC?

Anyone who did something like that? Would be very convenient not to have all routers be specially configured with port forwardings.