Boil cauliflower in salted water until tender, about 6-8 minutes. Drain well.
In a large bowl, whisk together your sauce: mayo, greek yogurt, vinegar, mustard, and spices.
Fold in remaining ingredients, including cooked cauliflower. It will taste great immediately, but for best results, refrigerate for at least 30 minutes so all of the flavors can meld together.