Mooching you normally use a banana weight (it's made out of lead no real banana's in the boat is the very first lesson) and I use a long leader, 8 feet, with a barrel in the middle of it which prevents twisting, stops seaweed from sliding to the bait and means less leader used when you need to change the hooks. Normally the bait is a cut plug herring. Here you want a good graphite rod so you can feel soft bites.
You can also mooch/jig darts, fake candle fish and the popular buzz Bomb without the extra weight as they are a weight themselves. Smear some scent on them though.
Mooching means you drift with the current and work your line up and down all depths. Myself I usually pull out about 25 feet of line, let it sit for ten seconds, ten more feet, let it sit, ten more, etc all the way down and then reel up ten cranks, fast when you hit bottom or you will hook a bottom fish, let it sit, ten more, etc. You generally want a line angle of 45 degrees or so so adjust your weight to fit that.
Usually you mooch in closer along kelp beds and shelves.
Salmon will hit on the way down, when it's sitting, or on the reel up so always be ready.