Opa's is a little German beach bar in Cabarete. They're only open for breakfast and lunch. You can, and we did, eat bratwurst in a roll, as well as various salads, pizzas, and the like.
When we were there, they had no German beer. Evidently there was some problem with importing, and they were waiting for it.
Did I mention it's relatively inexpensive, and you can show up in shorts and a swimsuit.