How to Make It
In a bowl, whisk the 2 cups of flour with the salt. Make a well in the center and pour in the water and oil, using a wooden spoon to gradually incorporate them into the flour until a shaggy dough starts to form. Turn the dough out onto a lightly floured work surface and knead until a soft dough forms, about 2 minutes. Wrap the dough in plastic and let rest at room temperature for 30 minutes.
In a bowl, combine all of the ingredients except the egg wash and sesame seeds and mix well.
Preheat the oven to 450°. On a lightly floured surface, roll out the dough to a 12-by-16-inch rectangle, a scant 1/4 inch thick. Cut the dough into twelve 4-inch squares. Spoon 2 tablespoons of the filling into the center of each square; bring up the 4 corners to meet in the center, then pinch together to seal. Arrange the pies on a parchment paper–lined baking sheet. Brush with the egg wash and sprinkle with sesame seeds.
Bake the pies for about 30 minutes, until lightly browned and the filling is hot. Let cool for at least 5 minutes, then serve warm or at room temperature.