Ingredients
4 small yellow onions (very thinly sliced)
4 tbsp capers (drained)
1 cup distrilled white vinegar
1/4 cup sugar
1 pound cream cheese (softened at room temperature)
1 cup sour cream
1 tbsp fresh dill or cilantro leaves, chopped, plus more for garnish
Sea salt and freshly ground black pepper
8 slices crusty whole-grain bread or baguette
8 ounces smoked marlin (or another smoked fish, such as smoked trout)
4 lime wedges

Method
In a small bowl, combine the onions, capers, vinegar and sugar and let sit for at least 1 hour. The pickled onions can be refrigerated for up to 1 week; you can simply keep adding fresh onions to the marinade.

In a small bowl, combine the cream cheese, sour cream, dill and pinches of salt and pepper and mix well with a wooden spoon. (Alternatively, you can blend in a food processor.)

Toast the bread and spread 1 tablespoon of the cream cheese blend on each slice. Layer the marlin thinly on top of the cream cheese on all 8 slices. Top with freshly ground black pepper and a squeeze of fresh lime. Serve open-faced, garnished generously with the pickled onions.