Place the water, celery, chorizo and chickpeas in a 4- or 5-qt. slow cooker. Cook, covered, on low until beans are tender, 8-10 hours. Stir in tomatoes, pasta and salt; cook, covered, on high until pasta is tender, 15-20 minutes., Freeze option: Freeze cooled soup in freezer containers. To use, partially thaw in refrigerator overnight. Heat through in a saucepan, stirring occasionally; add a little water if necessary.