Corned Beef with whites

1 lb white potato 1/2 teaspoon salt , to taste (corned beef is already salty) 1/2 teaspoon black pepper 2 -3 teaspoons vegetable oil 1/2 cup yellow onion ,[...]

12 ounces leftover cooked corned beef , cut into 1/2 inch cubes 1 lb baking potato , peeled, cut into 1/2 inch cubes 1/2 teaspoon salt 1 tablespoon butter 1[...]

2 tablespoons vegetable oil 8 ounces cooked corned beef , diced 1 white onion, finely chopped 1 bell pepper , finely chopped 2 medium baking potatoes , peeled[...]