If you have the watch paired correctly, by having "phone audio" (and probably "contact sharing") checked in the Bluetooth settings on your phone you should be able to call without touching your watch. I just tested it and by having "tilt to wake screen" on, I tilted my wrist to wake screen, said "ok Google" , and then "call Mike", and it dialed and connected call to watch via watch's speaker. If you have more than one phone number for the person you want to call, you will get asked "which number", unless you say (in my example) "call Mike mobile". The watch is treated as a Bluetooth headset speakerphone. Works fine.
I should add that I don't have a sim, and am just using via Bluetooth.