1
In a large serving bowl, combine the beans, dill, and olive oil. Season to taste and marinate for 10 minutes.
2
Blend together all of the mustard vinaigrette ingredients with a whisk or blender and season to taste.
3
Add the celery, onion, eggs, fennel, greens, capers, roasted tomatoes, and tuna to the bowl with the marinated beans. Drizzle with dressing and toss to combine.