Heat butter in large skillet over medium heat. Add onion; sauté 1 minute. Add tomato, water, potatoes and lima beans. Cover and simmer gently for 30 minutes or until beans are tender. (If using frozen beans, reduce the cooking time to about 20 minutes.)
During the last 5 to 10 minutes of cooking time, add the corn kernels. Season with the salt and pepper. If the mixture becomes too dry, add a little more water and correct the seasonings to taste, adding more salt and pepper as needed. The succotash should be thick but not dry. Serve warm. Makes 6 servings.