Combine beans, stock, water, salsa, chili powder, ground cumin, dried oregano in the bowl of a slow cooker. (See below for freezer tips.)
Slow cook on low for 9 to 11 hours. (The beans cook most evenly if cooked on low, so I don't recommend using the high setting.) The beans should be very tender when done.
Use an immersion blender to blend the soup. You can blend all of it until very creamy or just a portion of it if you'd like some whole beans to remain. (I like mine fully smooth, but this is personal preferance.)
Taste the soup and season with some salt and pepper, if needed.
If serving in bread bowls, use a knife to slice a circle in the top of each boule. Remove the circle and then use your hands to pull out the center soft part of the bread, leaving the crust intact. Warm in a 350 F oven for 10 minutes. Spoon soup into bowls.
Top soup with any of the additional toppings.