Hi Dlai,
The red meat inside the cunji is the right part to use, just cut a piece of it off, put through the hook couple of times and present it flat and nicely, then toss into the water and waiting for the hit.
There is a bag limit of 20 for using cunji. but that should be plenty for a good section. berley up with bread and some nice drummer will be on the chew.
Most of the rock fish will take cunji. drummer loves cunji whole a lot. 1/0 hook is my choice for drummer. groper takes cunji as well. but it usually got taken by other fishes before a groper sees it. You will also catch millions Kelpfish on cunji. Those pests generally take anything you throw into the water and i'ts dam hard to get back the hooks as they usually swallow the whole thing!
for crabs, you can buy those crab net from any fishing store. Those round and statium shaped one. get some pilchard or any smelly fish put into a stocking and crush them, then chuck into the net with some rocks to keep the net sit nicely underwater, toss it in some rock holes and wait for retrieve. There is also a bag limit of 10 for red rock crabs, so mind your takes.
Hope this helps...
Cheers,
dreaflym