The safe way to open a can of surströmming is to fill a bucket or a sink with water and open it under water. The fish pieces are supposed to be rinsed anyway.
If you do open it dry then the smell will be unbelievable - even if it has been stored properly. There are videos on Youtube of people vomiting from just opening a can. When I was a kid, some smart-ass thought it would be fun to open a can in the school's hallway: we had to evacuate that part of school for the rest of the day.
I have never tasted it (only smelled...) but I have been told that it tastes better than it smells.
Like other Swedish herring it is often eaten with boiled potato, onion, chives and sour cream. On a plate or wrapped in Tunnbröd, which you could get at IKEA. Some put it on Knäckebröd (also found at IKEA).
A middle-eastern food store could also have a soft flatbread that is just like Swedish "tunnbröd", just don't confuse it with a flat version of pita.
Oh yeah: Don't forget to drink schnapps and sing silly songs. Straight vodka is OK but if you could get a schnapps that is flavoured somehow (spices, orange or elderflower) then that would be more genuine.