A few weeks ago, while at the beach, I mentioned in passing to one of the residents that I liked uni or sea urchin. He offered to jump in the sea and get some for me. I accepted, of course, and he got his goggles and went on his way. Around 30 minutes later, he came back with a net full of the black, spiny creatures. He extracted the roe by chopping the body in half and rinsing it in a bucket of seawater to get rid of the grit. Apparently, fresh water will melt the roe. Ater rinsing, the roe was spooned into a container.
It was good, though not as sweet as the kind you can get in a decent Japanese restaurant. But I'm not complaining - it was free! I'll remember to bring some light soy and wasabi next time I go the beach.