Heat 1 tablespoon of oil in a large skillet over medium-high heat until hot. Add potato and stir a few times to coat evenly with oil. Add 1/4 cup water and cover immediately. Steam for 1 minute, or until the potato just starts to get tender. Transfer to a plate.

Add 1 tablespoon of oil into the same pan. Spread pastrami with minimum overlapping. Let cook without touching until the bottom side turns golden brown, 1 to 2 minutes. Flip and cook the other side until golden brown, about 1 minute. Turn to medium heat if the pan gets too hot.

Add the rest of the oil, celery, the white part of the green onion, Sichuan peppercorns, and chili peppers. Cook and stir for a minute, until the chili peppers turn dark brown, but not burned. Add the garlic and stir a few times.

Add the cooked potato. Stir for a minute, or until the potatoes are cooked but still crunchy.

Add the chili flakes/crisp, soy sauce and stock. Bring to a boil. Add back the pastrami, bell peppers, the green part of the green onion, and peanuts. Stir a few times to mix well. Transfer to a plate immediately.

Garnish with sesame seeds and serve hot as main.