Do you want to catch them in the salt or fresh water? I'll assume salt - its where I have the most experience with them.

Searching this as well as other web sites will turn up a wealth of info.

Look for gently sloping gravel beaches. Look for oysters and barnacles. Generally sandy beaches do not tend to hold searuns for any length of time. Different beaches will hold fish at different times of the year for various reasons. Baitfish is always a good thing to find. A beach that holds food will consistently produce searuns. Look for some fresh water sources. It can be anything from a little trickle of water to a fresh water spring or seep. After migrating back down from the streams it takes a little while for these guys to get accustomed to the salt water so they will hang around where the salinity isn't so high.

As far as specific beaches I'd suggest the Kitsap side of the Narrows. I don't know if you can still get down there with the bridge construction going on. In and around Joemma Beach looks like a pretty good place a little further south. Do some exploring there are a ton of unpressured beaches that hold fish. Have fun looking.

Steve