Make your dressing: In a bowl, whisk together the mustard, orange juice and zest, and honey. Slowly whisk in your olive oil until the mixture emulsifies. Season with salt and pepper.
Dress your salad: In a large bowl, toss together the radicchio, chicories, fennel and the dates. Drizzle with some of the dressing and half the breadcrumbs. Toss and adjust with more dressing, salt and pepper as needed and top with remaining breadcrumbs and some flaky salt.