Place the peas in a pot, cover with water and soak overnight. Drain the peas and set aside.
Place the onions, scallions, garlic and red bell pepper in a food processor. Set aside.
Place the pork bones, water, onion mixture, split peas, salt and pepper in a pot, and cook over medium low-heat for about 20 minutes.
Add the ground cumin, potatoes and cilantro. Cook for 30 minutes more or until the peas are tender. Add more water as needed if the soup becomes too thick.
Season with salt and pepper. To serve, top with avocado and fresh cilantro.
Notes
Leftovers keep well for about 3 days in the refrigerator in a covered container. This split pea soup will thicken as it cools, thin with a little water or broth if you want.