Sopa de Nopales

In a large saucepan combine nopales, two of the scallions, and 3 cups water. Bring to boiling; reduce heat. Cover and simmer 20 minutes or until nopales turn dull olive green. Remove and discard scallions. 2. Meanwhile, in a large skillet cook onion, garlic, and a pinch black pepper over medium 10 minutes or until onion is translucent, adding water, 1 to 2 tablespoons at a time, as needed to prevent sticking. Add tomatoes and oregano; cook 5 to 7 minutes more or until tomatoes are tender. 3. Transfer sautéed vegetables to saucepan with nopales. Stir in beans, corn, peas, and 1 cup water. Season with salt and black pepper. Cook 10 minutes to blend flavors. 4. Meanwhile, thinly slice remaining scallion. Garnish soup with scallion and, if desired, crushed red pepper. Serve with lemon wedges.