Ingredients ¾ cup finely chopped celery ½ cup coarsely chopped arugula ¼ cup mayonnaise ¼ cup thinly sliced scallions, white and light green parts only ¼ cup whole-milk plain Greek yogurt 1 teaspoon grated lemon zest 2 tablespoons lemon juice 1 ½ tablespoons capers, rinsed ½ teaspoon dried tarragon, rubbed 2 (5 ounce) cans solid