In Lerici, Ciccillo a Mare is a great place for a seafood lunch overlooking the sea, in a semi-secluded location. Go through the tunnel under the castle (that looks like it goes nowhere), then turn right when you come out of the tunnel. You’re at Ciccillo a Mare, a hidden restaurant with a terrace overlooking the sea. Try the polpo (octopus) or cozze (mussels).
There’s also a small beach at Ciccillo a Mare if you want to swim or lay on the beach.