Soak the dried chickpeas overnight in a large bowl covered by 2.5 cups water. Cover with kitchen towel and set aside. If using canned chickpeas, skip this step go to Step 2 below.
Drain and rinse the chickpeas. To a large saucepan or skillet over high heat add the chickpeas and baking soda. Toss to coat and dry cook 2-3 minutes, stirring often.
Add the 6.5 cups of water and bring to a boil. Cook for 30 minutes (See Note 4) over medium heat. Skim any foam and skins that floats to surface. Chickpeas are done when they break up easily when pressed between thumb and finger. Drain and transfer to food processor. At this stage you can pick through to remove any skins, but I feel the food processor going at 5 minutes does a fantastic job of creating a creamy texture.
Process cooked chickpeas to a thick paste. Stop and scrape down the sides. With motor running add the tahini, lemon juice, garlic, salt and cumin. Next, with motor still running, drop in the ice cubes and mix for a total of 5 minutes. You want the creamiest, smoothest paste. (For a spicier version see Note 5 below).
Transfer to a bowl, cover and allow to rest at least 30 minutes, or refrigerate if not eating immediately. Allow to come back to room temperature before spooning on to a serving plate. Garnish with a drizzle of good olive oil, parsley and either sumac, dukkah or za’atar.