In a large stockpot, cover the beans with water, covering them by 2 inches. Add bay leaf, cumin, oregano, and Italian pepper. Simmer until the beans are tender, about 45 minutes.
After 45 minutes, remove the pepper.
In a saute pan, saute onions, red, and green peppers until translucent. Puree in a blender, this is the sofrito.
In the same pan, saute the garlic. Add to the beans, along with the sofrito, 1/4-cup olive oil, sugar, and vinegar. Season with salt and continue to cook until very thick, about 45 minutes. Garnish with finely chopped red onion.