Drain the beans and place in a stockpot or large clay olla. Add the avocado leaves if using, the garlic, hoja santa leaf if using, the onions, canola oil, epazote and 10 cups of water. Cook over medium-low heat until fully cooked, stirring occasionally, 1 hour 30 minutes.
When the beans are fully cooked, remove the onion and garlic. Season with salt and serve.