This can be simple or complex based on what you want to tie and fish with. The only Kokanee I have seen down your way were in the S. Platte and they were ripe when I discovered them so I didn't try to catch any. Since the fish are land locked they have grown up on the standard fare in the watershed that they live in so when they are fresh into the spawning season I would try showing them small Sculpins patterns and the like. If this did not work and I were going to go to an attractor pattern like typical salmon flies are representative of. This is where you have to choose between simple or complex.
Here in AK. those who want simplicity use what has come to be known as The Russian River Fly. These are just a hook with no body and they have a red & white buck tail wing as long as the hook. I have not used the RRF but have had good catches of sockeye using the Skykomish Sunrise and Freight Train. These are fairly simple when compared to elaborate salmon flies but still give you that "I caught them on a classic pattern" feeling at the end of the day. For pictures and recipes of these two and others that will all catch a sockeye take a look here: Flies for Alaska - The North American Fly Fishing Forum
There are 2 threads full of patterns. Some are simple and others are work. The flies for Salmon thread has Polar Shrimp patterns on it and they would be another red / orange choice. The steelhead & salmon thread has the Skykomish and Freight Train in it. As said in the opening sentence it is a matter of what you want to fish. A Bunny Fur Comet in red or orange catches them here too. These are in the Salmon thread.
Hope that is of some help, there has to be a book about Kokanee patterns down there somewhere. If not you can just make them up, I have done plenty of that