Whisk together the mayo, apple cider vinegar, sugar, Dijon mustard and salt. Add to the vegetables and mix to combine. Refrigerate for 1 hour to allow the flavors to meld and the broccoli to become soft (you can eat right away but the broccoli is crisp and has less of the traditional texture).
Meanwhile, place the sunflower seeds, soy sauce, sugar, smoked paprika, and 2 pinches kosher salt in a skillet. Heat over medium low heat and sauté for about 5 to 6 minutes, stirring frequently, until they are sticky and most of the liquid is evaporated, taking care that they do not burn and scraping any sticky bits from the bottom of the pan. When they are sticky and darkened in color (and may have clumped together), remove from the heat and spread them onto parchment paper in a single layer and allow them to dry until serving, about 10 minutes.
When ready to serve, top the salad with the sunflower seeds.