Maracatu: It's a restaurant with a vegetarian theme, serving fresh seafood as well. They often have live music, and they serve a local Costa Rican craft beer on tap.
The Refuge: A killer burger joint just down the beach, towards the south. It's underneath the hostel called Pyramis. Huge burgers, made with fresh ingredients. Really a treat, when traveling!
Dominical has a couple small markets, an ATM just up the road on the highway (walking distance), and several hostel options. You can also camp on the beach. Infact, most places in Costa Rica you can camp on the beach, but you should use caution, especially if you walk away from your belongings even for a minute. We witnessed a guy, on his last night in Costa Rica, camped on the beach in Dominical, walk over to the bar for a beer, and when he returned to his hammock and bag, they were both gone. Luckily his passport was in his pocket, but it was a necessary reminder to us, and all, to watch your stuff!