If using fresh herbs, make an herb packet by placing a large square of cheesecloth on a counter. Place the thyme, rosemary and half the oregano in the center, gather the ends together and tie to enclose. Remove the leaves from the remaining bunch of oregano, chop and reserve.
Combine the beans, fresh herb packet or the dried herbs and water in a large saucepan or stockpot. Bring to a boil, reduce to a simmer and cook, covered, until the beans are cooked through but still firm, 1 hour. Remove from the heat. Lift out and discard the herb bundle.
In a large stockpot, heat the olive oil or butter over medium heat. Saute the onions until golden, 15 to 20 minutes.
Stir in the garlic and cook just until the aroma is released, about 5 minutes. Add the tomatoes and their liquid, salt, pepper and half of the reserved chopped oregano (if using fresh). Reduce the heat to medium low and cook, stirring frequently, until the liquid is evaporated. Stir in the beans and their cooking liquid and cook 5 minutes longer.
Pour in the vegetable stock or water. Bring to a boil, reduce to a simmer and cook about 40 minutes, or until the beans are very tender.
Serve hot, garnished with the remaining chopped fresh oregano and lime wedges.
c.1997, M.S. Milliken & S. Feniger, all rights reserved