Kilowatt in the Mission gets NHL Center Ice, and is a reliable place to watch your games during the playoffs, if you just want to be surrounded by hockey fans. Bit hipstery, but the overall vibe is very friendly.
There is a bar called Hockey Haven in the Richmond somewhere. It is nothing of the sort; do not go there.
Assuming they play hockey this year, I mean.
As a Canadian, I found Greens sports bar to be very accommodating. They turned on a couple TV's to the hockey game when we were there a couple years ago, and while I don't think they had Molson products, that's not a bad thing. they did have a huge selection of beer which should satisfy anyone and their happy hour is pretty cool.
As for Hockey not being big here, we met a ton of Sharks fans while we were in SF. I'm in Napa right now and met a few just a couple hours ago, so Hockey might be a little bit bigger than you think here.