Cook the cauliflower on the stove or in the microwave.Stove method: Boil a pot of water with a tablespoon of salt. Add the cauliflower, and simmer until very tender (about 5 minutes). Drain well and let cool.Microwave method: Place the cauliflower florets in a large bowl with 2 tablespoons (30 mL) of water. Microwave on high for 10 minutes, stirring halfway through. Drain well and let cool.
Meanwhile, in a small bowl, whisk together the mayonnaise, apple cider vinegar, Dijon mustard, garlic powder, paprika, sea salt, and black pepper, until smooth.
In a large bowl, combine the cauliflower, diced onion, sliced celery, and diced egg.
Pour the dressing over the salad and mix well.
If you have time, refrigerate the cauliflower potato salad for at least 1 hour to let the flavors develop. (This is optional.) If desired, garnish with chives and additional paprika.