Console monitor on different wifi network
The Yun is just an ordinary network device.  However, the tools you are provided with use a system called mDNS to find the Yun.  That only works across the same local subnet that you are on.

If the Yun is on a different subnet then you will have to (assuming the routing between subnets is working fine) do it manually by knowing the IP address of your Yun.  Use that IP address in place of "arduino.local" or whatever your Yun is called.