Praia do Salto is wonderful. Its it's on the coast road from Sines near Porto Covo, we found it difficult to spot......but then it is secluded. Yes, you have to go down steps to reach it but they were ok (and I'm scared of heights!) and nothing to worry about.
Praia do Salto is a recognised naturist beach and the few people we met there were naturist too. Mid week you have the place almost to yourself. It really is pretty, so quiet, we were free to enjoy the sun. Take your own water and snacks if you intend staying as there are no facilities. A typical laid back beach for chilling and perfecting your all over tan! Don't go there expecting a family day out, it's not a sandcastles beach(unless of course you are a naturist family).