Put the chickpeas in a strainer and pick through to remove any small stones; rinse well.
Transfer the chickpeas to a large bowl and add 8 cups water; stir in the baking soda. Set aside to soak at room temperature, at least 12 hours and up to 1 day.
Drain the chickpeas and rinse well. Transfer to a large pot and add 10 cups water; bring to a boil and cook 5 minutes, then reduce the heat to low and simmer until the chickpeas are very soft, skimming off any foam from the surface, about 45 minutes.
Reserve 1 cup of the cooking water, then drain the chickpeas and rinse under cold water. Transfer to a food processor and puree until smooth. With the machine running, add the tahini, olive oil, garlic, lemon juice, cumin, red pepper flakes, paprika, 1 teaspoon salt and the reserved cooking water; puree until smooth and creamy, about 5 minutes.
Transfer the hummus to a bowl, drizzle with olive oil and sprinkle with paprika. Serve with pita bread and/or vegetables. To store, cover and refrigerate 3 to 4 days.