If you tell the watch to forget the initial WiFi network it sees (but tries to use DHCP with) and scan for others, you will then have the ability to specify static IP, gateway, and DNS values by tapping on the name. If already connected to the phone via Bluetooth, you may need to temporarily disable Bluetooth in order to fall back to WiFi in order to configure it. You can also look up the watch's MAC address under Gear info, About device.