Place the chickpeas and the baking soda in a large pot and add enough water to cover the chickpeas by 2 inches. Bring to a boil over medium-high heat, then partial cover the pot and reduce the heat to a simmer. Allow to cook for about 60 minutes, or until the chickpeas have begun to fall apart. Skim the skins from the top of the water then drain the chickpeas. (If you can't get all of the skins out the water, it's okay.)
Place the chickpeas in a food processor, and process until it becomes a paste. Squeeze the roasted garlic out of the papery skin into the food processor, and then add the tahini, lemon juice, water, and salt. Process until smooth and creamy. Stir in the chopped chives.
Transfer the hummus to a bowl and top with the olive oil, sumac or paprika, and extra chives, if using.
Refrigerate until ready to eat. Serve with pita wedges or cut vegetables.