For the citrus dipping sauce: Place all ingredients in a large bowl and whisk until well combined. Season, to taste, with salt and pepper.
For the brisket pot stickers: In a large pot place the brisket piece and peanut oil and cook on low heat for approximately 7 hours until brisket begins to fall apart. Remove cooked brisket from the oil and allow to slightly cool. While brisket is cooling, saute the diced onion with the butter until translucent. Place the onions in a large bowl. Once the brisket has cooled, chop into a small dice and add to the onions. Add the chiles, garlic and cilantro and season the mixture with salt and pepper, to taste.
Fill each dumpling wrapper with a small amount of the brisket mixture. Seal the edges with the beaten egg.
Bring a medium size pot of water to boil. Place the pot stickers in the boiling water and cook for approximately 2 minutes. Once the pot stickers are cooked, transfer them to a paper towel-lined plate to drain before adding them carefully to the hot saute pan. At the same time, in a medium size saute pan, heat a little olive oil until slightly smoking. Working in batches, sear both sides of the pot stickers until golden brown. Remove from the pan and place on more paper towels to soak up excess oil. Repeat with remaining pot stickers. Serve immediately with a side of the citrus dipping sauce.