½ red onion ½ cup white balsamic vinegar 1 teaspoon sugar ½ teaspoon Kosher salt 5 ounces baby arugula ¼ cup fresh flat-leaf parsley, chopped ¼ cup fresh mint, chopped 2 pounds fresh peaches, peeled and pit removed ¾ cup crumbled feta cheese ½ cup toasted pistachios ¼...
