We visited Mal Pais in the low season (mid-September) and much in the area was closed so we guessed a hotel restaurant like Nectar might be open and were right. It's a 15-20 minute drive northwest from the main crossroads of Mal Pais to Flor Blanca hotel so you need a vehicle. The restaurant is set near the beach and has a large roof that makes it a little dark but also keeps it cool. We had fish tacos and pulled pork tacos which were very good and a Costa Rican artisanal beer. They also let us use their beach area which seemed fair as the restaurant prices are not cheap (though the pool is for hotel guests only). The beach is very steep so the waves get big at the shoreline but it felt fairly safe as it is narrow strip bordered by rocky headlands.