So I might just be slow, but I can't for the life of me get a KMC missing link to unhook. Its a two piece link each with half of a normal link-- it seems like you should be able to just push the link together and viola it comes apart, but I can't get it. What the hell am I doing wrong? I feel so dumb.

i used my magic link on a kmc chain, and then it broke.

do yourself a favor and take it off.

I'm trying to take it off-- I can't get the ****ing missing link apart.

The KMC links are strictly one time use. They have little teeth that stop the thing from coming apart again.
If you have a decent shop grade chain breaker, you can pop the pins out.

I use the SRAM links on my off road singlespeed that has a much smaller chainring than a road going fixed, thus much higher chain tension and I haven't had any trouble.