Preheat oven to 400°F. Line a rimmed sheet pan with parchment.
Toss pumpkin with 1 tbsp oil, a pinch of salt, and pepper. Spread on the pan.
Roast 20–25 minutes, stirring once, until tender and caramelized. Cool briefly.
Blend tahini and lemon juice in a food processor until light and creamy.
Add garlic, cumin, maple syrup, and remaining 2 tbsp oil. Process to combine.
Add chickpeas and roasted pumpkin. Blend until mostly smooth, scraping the bowl.
With motor running, stream in cold water until fluffy and silky.
Taste and adjust salt, lemon, or cumin as needed. Pulse to mix.
Swirl into a bowl. Sprinkle smoked paprika and pepitas. Drizzle a little oil.