Lexical, I must admit Mint isn't one of my favorite herbs, I would prefer to pair fresh thyme and some pepper and lemon personally, but what comes to mind is the one thing I love that is mint, and it goes well on just about everything:
http://www.wikihow.com/Make-Mint-Chutney
Not sure if it's the best thing for Salmon but I like Mint Chutney as a condiment on other stuff.
If I wanted to make some simple nice grilled Salmon, I would probably make a compound butter.
Let a stick of butter get soft "room temp", dice up some FRESH herbs "mint, basil, thyme, chives, dill" etc... mince up a shallot if you want "optional" whip it all together in a bowl, add a dash of salt & pepper, maybe a drop of Tabasco and or Worcestershire sauce/ or Maggi's
mix it all together but don't let it melt,
from here you can put back in fridge or get fancy and roll it up in some wax paper so you can slice off disks after it hardens back up.
any ways, just put some on top of your grilled salmon or other meat and serve, it will melt into a delicious sauce