1. Thinly slice the red onion and place in a bowl of water to soak until the rest of the salad is ready; this will neutralize the astringent flavor.
2. Cook the broccoli in a steamer basket by gently steaming it over boiling water for 5 minutes or until just tender. Once the broccoli is cooked, submerge it in an ice bath to stop the cooking if you aren't serving immediately.
3. To make the sauce, place the garlic in a food processor and pulse until minced. Add the tahini, nutritional yeast, paprika, mustard powder, turmeric, salt and pepper, apple cider vinegar, and oil, then pulse until silky smooth. The sauce should be quite thick, but if it is too thick, add water 1 teaspoon at a time until you reach desired consistency.
4. Place the broccoli and sliced onions in a large bowl and toss with the sauce. Top the salad with goji berries and pumpkin seeds. Serve broccoli and goji berry antioxidant salad warm or chill before serving.