In a large bowl, combine chickpeas, 8 cups fo cold water, and 2 tbsp kosher salt. Let soak at least 12 hours, or overnight
In a large stockpot over high, bring another 10 cups of water and the baking soda to a boil
Drain the soaked chickpeas, discarding soaking water, and add to pot
Return to a simmer, then reduce to medium and cook until the skins are falling off and the chickpeas are very tender, 45 - 50 minutes
Set a mesh strainer over a large bowl and strain the chickpeas into it. Reserve 3/4 cup of the cooking water
Let sit for 1 minute to let all liquid drain. Set aside about 2 tbsp chickpeas, then transfer the rest to a food processor. Add remaining 1 tsp salt, process for 3 minutes
Stop the processor and add tahini. Continue to process until mixture has lightened and is very smooth, about 1 minute
Use a rubber spatula to scrape the sides and bottom of the food processor bowl. With the machine running, add 3/4 cup cooking liquid and lemon juice
Process until combine. Taste and season with salt
Transfer to shallow serving bowl and use a large spoon to make a swirled well in the center
Drizzle with olive oil, then top with the reserved 2 tbsp chickpeas, parsley, cumin, and paprika