In a large stockpot, bring 4 cups of water to a boil, with the onion and garlic. Lower heat, add the squash and cook covered for 5 to 8 minutes. Add the squash vine greens, squash flowers, cilantro and hierba buena to the soup. Allow to cook covered for at least 15 to 20 minutes, or until all is soft. Season with salt. Ladle the soup into bowls and serve with lime wedges and pickled chiles/vegetables.