To make the salad, preheat the oven to 425°F (218°C). Line a large baking sheet with parchment paper.
Place the cauliflower florets in a large bowl, and then drizzle them with the tamari. Use a large spoon or rubber spatula to gently stir the florets to coat them with the tamari.
Sprinkle the florets with the nutritional yeast, garlic powder, black pepper and salt and gently stir them again to combine the ingredients. Spread the cauliflower florets on the prepared baking sheet. Roast the cauliflower for 25 minutes, until the edges of the florets are golden and crispy.
While the cauliflower is roasting, prepare the tahini sauce. In a medium jar, use a fork to whisk together the tahini, lemon juice, salt and garlic powder.
Add 4 tablespoons (60 ml) of water and mix the ingredients together completely. Add up to 2 tablespoons (30 ml) of more water, until the desired consistency is reached. Taste the dressing and add more salt and lemon juice if desired.
Transfer the roasted cauliflower to a large bowl. Add the parsley, dates and sunflower seeds and stir to combine the ingredients. Divide the salad among four serving bowls.
Drizzle each serving with the tahini sauce and serve the salads immediately.