In a large pot or Dutch oven, saute the bacon until crisp. Remove the bacon an set aside for later. To the bacon grease add onions, bell peppers, and the white and light colored part of the scallions. Cook over medium heat, stirring, until the vegetables have softened, about 5 minutes. Add potatoes, half of the corn, 2 cups of water, salt, black pepper, and cayenne. Bring to a boil, cover the pot, and reduce the heat to low. Simmer until the potatoes are tender, 10 to 15 minutes.