Cover dry beans with water and let stand covered overnight. Drain and discard water.
Place the cleaned black beans in a large 6-quart saucepan. Add water and olive oil—this will prevent the beans from foaming. Bring the beans to a boil, reduce heat to low, cover, and cook until the beans are tender, about 1 hour.
Do not add salt to the beans when they are cooking. Salt at this stage of the game will make your beans very tough.
You may also cook the beans in a pressure cooker. Follow the manufacturer’s directions for exact times, but our pressure cooker takes about 20 to 25 minutes to cook the beans completely.
Whichever method you use, do not drain the water from the cooked beans.
Meanwhile, chop onion and green pepper. Mash the garlic with salt and peppercorns in a mortar and pestle.
Sauté the onions and green pepper in olive oil until the onions are translucent. Add mashed garlic and sauté another minute or so.
Add the cooked beans, oregano, cumin, bay leaf, vinegar, and wine. Cover and simmer over low heat for 15 to 20 minutes, stirring occasionally. Remove bay leaf.
Some cooks—including us—like to thicken the beans by taking about 1 cup of beans and mashing them to make a thick paste. Mix the mashed beans back into the pot.
Add additional salt and pepper to taste.
Stir in the sugar; then drizzle a couple of tablespoons of olive oil over the beans. Immediately cover the pot, remove from heat, and let stand for 10 minutes.
Serve the by now fantastically prepared black beans over white rice.
You may garnish the beans with cilantro and chopped white onions. Not only do they look good presented this way, they taste even better than they look.