Pre-heat oven to 425 degrees and line two baking sheets with foil.
In a large bowl, toss together cauliflower florets, olive oil, chili powder, garlic powder, salt, and pepper.
Spread cauliflower in a single layer on a baking sheet. Place sliced lemons in a single layer on the second baking sheet.
Bake cauliflower for 25-30 minutes, tossing it once halfway through the cooking time, until it's turning golden. Bake lemons 18-24 minutes, flipping after 12 minutes, until they are nice and caramelized.
Remove from oven and let cool slightly before arranging cauliflower on a platter and topping with pomegranate arils, crumbled feta cheese, pine nuts, and chopped parsley. Top with roasted lemons and drizzle tahini dressing over the salad.