Hello everyone!
Now that the betatesting of Overwatch has been made available to all, I've gotten a chance to muck around in-game a bit, and I believe I've come up with a way to make your enemies even saltier.
It involves the ''Well played'' speech bubble spraytag from Hearthstone and the killcam!
Once you've killed your opponent, simply put this tag on the ground and make sure your opponent can read it when watching the killcam.
This should make your opponent much more salty, certainly worked on me.