In a large pot, bring salted water to a boil. Add the baby potatoes and cook until tender, about 15-20 minutes. Drain and let cool.

In a mixing bowl, whisk together olive oil, lemon juice, lemon zest, dill, Dijon mustard, salt, and pepper until well combined.

Once the potatoes have cooled, add them to the bowl with the dressing. Add diced celery, red onion, and cherry tomatoes. Toss gently to coat.

Cover the salad and refrigerate for at least 30 minutes to allow flavors to meld. Serve chilled.