Cover potatoes with water in large saucepot; bring to a boil over high heat. Reduce heat to low and simmer until potatoes are fork-tender, about 15 minutes. Drain and set aside.
Heat oil in large skillet over medium heat and cook onion, stirring occasionally, until tender, about 5 minutes. Add potatoes and cook, tossing gently, until potatoes are crispy, about 8 minutes. Stir in garlic and cook 30 seconds.
Crumble in the corned beef; stir to combine. Stir in remaining ingredients. Cook, stirring occasionally, until heated through, about 5 minutes. Serve, if desired, with fried eggs.