In a large bowl, combine flour, salt, warm water, and oil to create a smooth mixture. Knead the dough on a floured surface for about 5-7 minutes until soft and elastic. Cover with a damp towel and let it rest at room temperature for 30 minutes.

In a mixing bowl, combine ground beef, chopped green onion, onion, oyster sauce, soy sauce, black pepper, grated ginger, and additional water. Mix thoroughly until well incorporated and adjust seasonings as desired.

Dust your work surface with flour and roll the dough to about 1/8-inch thickness. Cut it into 8 equal pieces. Place approximately 2.5 tablespoons of the beef filling on one half of each piece, fold over, and pinch the edges together.

Lightly dab the smooth side of each pie with water and press a mix of black and white sesame seeds into the dough.

In a frying pan, heat a generous amount of oil over medium heat. Fry each pie for about 4 minutes or until golden brown, then flip and cook for an additional 3-4 minutes.

Remove the pies from the pan using a slotted spoon and place them on a plate lined with paper towels to absorb excess oil. Let them cool slightly before serving.