Drain chickpeas. Place in saucepan with half the onions and garlic, baking soda and 4 cups water. Boil, reduce heat and cook uncovered over low heat for 3 hours or until chickpeas are tender but not mushy. Drain well. Saute remaining garlic and onion in oil for 5 minutes, then add chickpeas and chorizo and saute for 3 minutes. Add parsley, salt and pepper. Serve hot.