Place the dried chickpeas in a large bowl and cover with about 6 cups of water.
Stir in 1 1/2 tablespoons of the kosher salt and the baking soda, then soak the chickpeas for at least 12 hours and up to 24 hours, preferably overnight.
After soaking, drain and rinse the chickpeas well.
Stovetop method: Place the drained chickpeas in a large pot or Dutch oven and cover with 3–4 inches of fresh water. Add 1/2 tablespoon kosher salt, bring to a boil over high heat, then reduce to a simmer, cover partially, and cook about 2 hours until tender, skimming any foam from the surface.
Instant Pot method: Put the drained chickpeas in the Instant Pot with about 6 cups of water and 1/2 tablespoon kosher salt. Seal the lid and pressure cook on high for 20 minutes, then allow a natural release for 10–15 minutes before opening.
Slow cooker method: Add the drained chickpeas to the slow cooker with about 8 cups of water and 1/2 tablespoon kosher salt. Cook on high for about 4 hours or low for about 8 hours, until the chickpeas reach your desired tenderness.
Let the cooked chickpeas cool in their cooking liquid, then transfer them with some liquid to airtight containers and refrigerate for up to 4–5 days or freeze for longer storage.