Preheat your oven to 200°C / 400°F.
Spread the cauliflower florets out into a single layer on a baking sheet. Drizzle with extra virgin olive oil, adding more as needed to make sure the cauliflower is well coated. Sprinkle with cumin, chili powder, salt, and pepper, and toss to evenly coat the cauliflower with the spices.
Place the cauliflower into the oven and roast for 15 minutes.
Remove from the oven, turn the cauliflower, and sprinkle with the pumpkin seeds.
Replace in the oven and roast for another 10-15 minutes, until the cauliflower is golden and the pumpkin seeds are toasted.
While the cauliflower is roasting, prepare the hummus.
Combine chickpeas, tahini, garlic, lemon juice, and salt in a food processor. Pulse a few times to break down the chickpeas.
With the food processor running, add the cold water in a slow stream. Stop the food processor and scrape down the sides. Taste, adjust seasonings, and add any extra water to achieve the desired consistency.
To serve, spoon hummus into the bottom of four bowls. Spread and swirl into an even layer. Add 1/4 of the roasted cauliflower and pumpkin seeds over the top of each bowl.
Drizzle with good olive oil, sprinkle with salt and pepper. Serve with warm pita bread.