I prefer to do this one on high to be sure and get the beans soft enough since we’re not presoaking them. You may need to check it throughout the day and add more water. If you plan to be gone a lot of the day, add more water than you think you need. It’s better to be more soupy than to run out of liquid in the pot while you’re cooking it.
If you’d like to prepare this meal as a Freezer to Slow Cooker meal, all you need to do is chop your ham and onion, put it into a freezer bag with the cumin and salt. Freeze. On cooking day, follow the instructions above.