A downrigger rod or steely stick off a downrigger with a very shinny flasher and bare red hooks behind it.

I'm not sure if anybody has every tried to fly fish for them. You might be able to get some to bite any Alaska sockeye pattern or nymph on the lower Cedar when it opens but I'm not sure if it is open durring the run and you aren't supposed to target them. As for fly fishing the lake your on your own. Since it is usually only open for a few days 99.999% of people troll for them using what I gave you above. To really answer your question, if you know what depth to target, try usuing a small size 8 or 6 Krystal Shrimp or something along that line. Since sockey are really attracted to flash this might be you best bet.

Here's an idead, try using a small, size 6 or 8, Flash fly made from different colors of Flashbou. Try red, orange, blue, silver, or pearl. I could be on to something here. Except you relly need to know the fish's depth and know that your fly is at that depth.

I know I'm kinda rambling here but these are just ideas.