Place a wok over high heat until hot. Add oil, swirling to coat sides. Add meat, onions and green onions and cook, stirring, until meat is browned and just cooked through, about 5 minutes. Add sauce and cook, stirring, until sauce boils and thickens slightly. Remove from heat and let filling cool.
Preheat oven to 375°F Roll out pastry on floured board to a thickness of 1/8 inch. Using a 3-inch round cookie cutter cut out 20 circles. For each turnover, place 2 teaspoons filling on half of a round, moisten edges of dough with water, then fold other half over to enclose filling. Crimp edges to seal.
Place turnovers 1 inch apart on lightly oiled baking sheets; brush with egg yolk mixture. Bake until golden brown, 25 to 30 minutes. Serve warm with chutney on the side.