Break down cauliflower into bit-size florets. Bring a pot of water to a boil and ready an ice bath. Blanch Cauliflower for 4 minutes, just enough to make it tender with a bit of crunch still left. Drain and plunge into the ice bath to stop cooking.
In a bowl, toss together the blanched cauliflower with sliced red onions and sunflower seeds. Make yogurt dressing according to directions. Add to cauliflower and stir until well coated. Let refrigerate for at least an hour before serving.