Soak a thinly sliced red onion in water for 15 minutes; drain. Whisk 1 1/2 tablespoons dijon mustard, 2 tablespoons white wine vinegar and 1 tablespoon capers. Whisk in 1/3 cup olive oil, and salt and pepper to taste. Toss with 1 pound shredded carrots, 2 thinly sliced celery stalks, the onion slices and 1/4 cup chopped dill.
Photograph by Antonis Achilleos