Nai Fohl
Advocatus Diaboli
I hate NJO Luke in versus threads. Hell...
NJO Luke will defeat Kun.
For force powers they might be both very equal but since Luke
a) knows Sith powers
b) will use them because of NJO philosophy BS
c) will utilize his "bad" feelings to overcome Kun
That actually would make him more powerful than Kun because the real cool stuff Kun did was Sith magic. Now we know that Vodo simply resisted the effect of the spell Kun did freeze the Senate with so that kind of stuff may not affect powerful people and I guess NJO Luke can be considered more powerful than Vodo.
So we're coming to duelling skills. While Kun is - without a doubt - a major badass in lightsaber combat but he has two major problems here:
a) Luke is wearing two lightsabers and this is the worst thing that can happen to somebody with an double bladed lightsaber because the advantage of this weapon is nullified in this case
b) Luke - in terms of duelling skills - has to be considered to be a match for anyone else as he is so damn fast that he looks like wielding 20 lightsabers at once. So you can actually see him as a bigger version of Yoda (and believe me: I hate to do so because I hate this kind of NJO BS)
Now it's very hard to decide but since Luke could compete with thousands of aliens of whom one was to powerful for Kyp Durron (who is not that shabby himself) he might be able to kill Kun although this will be a nice fight to see and Kun might be able to kill Luke as well but I just say Luke has the better chance.