Place the onion, garlic, scallions, tomatoes, achiote, cumin, and 3 tablespoons of water in the blender and blend until a paste is formed.
Drain the garbanzo beans and place in a large pot and add the water, onion mixture and pork hocks. Over medium-high heat, bring the beans to a boil, then cover the pot and reduce the heat to medium-low. Allow the beans to cook until almost tender, approximately 1 hour and 30 minutes.
Add the carrots and potatoes and cook for 30 minutes more or until the beans are tender.
Add fresh cilantro and serve with white rice and avocado on the side.