Rinse the dried chickpeas and place in a large bowl; cover with 3 inches of cold water and soak 12β24 hours.
Drain, transfer to a pot, cover with fresh water by 2 inches, and bring to a boil; stir in the baking soda, reduce to a gentle simmer, and cook until the chickpeas are very tender and easily crushed between fingers, 45β60 minutes. Drain and cool 10 minutes.
In a food processor, combine the garlic and kosher salt and pulse to a fine paste, about 10 seconds; add the fresh lemon juice and let stand 5 minutes to mellow.
Add the tahini and process until thick and creamy, 30β60 seconds; with the motor running, stream in most of the ice water until the mixture turns very pale, light, and fluffy, 1β2 minutes, reserving a little to adjust consistency later.
Add the canned pumpkin puree, ground cumin, smoked paprika, extra-virgin olive oil, and all of the cooked chickpeas; process until completely smooth, 2β3 minutes, scraping the bowl once or twice. If too thick, blend in a splash of the reserved water until soft and spreadable.
Taste and adjust seasoning as needed; transfer to a container, press plastic wrap onto the surface, and chill 30 minutes to let flavors meld.
Spoon into a shallow bowl, make a swirl, and top with pumpkin seeds and flat-leaf parsley. Serve with warm pita, crackers, or raw vegetables.