Combine water and salt in the slow cooker. Leave on high for 1 hour.
Meanwhile, in a separate bowl, combine remaining ingredients. Form into balls and rest in fridge for 20 minutes.
Add matzah balls to slow cooker. Cook for approximately 3 hours on low. Allow to cool, then freeze on a cookie sheet lined with parchment paper, for about an hour. (This helps the matzah balls not stick to each other when frozen together.) You can then transfer matzah balls to small loaf pans, containers, or Ziploc bags to freeze in portions.