Briny capers infuse this lemony vinaigrette. When tossed with a mix of bitter arugula and radishes, the salad symbolizes one of the traditional elements on the seder plate.
Whisk together capers, lemon juice, salt, and pepper. Gradually add olive oil, whisking constantly. Combine arugula, celery leaves, parsley, radishes, and scallions in a large bowl. Pour vinaigrette over salad, and toss to coat. Drizzle with additional oil and lemon juice if desired. Season with salt and pepper.