Preheat oven to 425 degrees. Line a large rimmed baking sheet with parchment paper.
In a large bowl, toss potatoes with oil, salt and pepper. Place potatoes in an even layer on the lined baking sheet.
Bake for 20 minutes. Flip and bake another 15 to 20 minutes or until golden brown.
Top each potato coin with 1 to 2 tsp cheese and 1 tsp chopped corned beef. Broil for 1 to 2 minutes until cheese is melted.
In a small bowl, stir together ingredients for the pico de gallo.
Top with avocado, pico de gallo, jalapeƱo and a dollop of sour cream.
Sprinkle with green onion and cilantro.