In a bowl add all the cauliflower florets with the lime juice, salt and pepper, and olive oil and mix well. Transfer the cauliflower florets to a cookie sheet and bake in the hot oven for 25 minutes.
Meanwhile in a bowl combine the lime juice, garlic, mustard, mayonnaise, and olive oil. Stir and add more oil if too pungent. Season to taste. (This dressing can store well in the refrigerator for up to a week)
Place the cauliflower florets in a bowl and add the mustard lime dressing to your liking. Add the fresh tarragon and serve.