In a small skillet heat oil over medium heat. Add garlic, cumin, and coriander. Cook and stir for 30 seconds. Transfer oil mixture to a food processor or blender. Add chickpeas, pumpkin, water, lemon juice, salt, and cayenne pepper. Cover and process or blend until smooth, scraping sides as necessary.
Transfer hummus to a serving bowl. Cover and chill for at least 2 hours to blend flavors. Sprinkle with pumpkin seeds. Serve with vegetable dippers.