In a large skillet over low heat, warm vegetable oil. Add the white onion, scallion, red bell pepper, and green bell pepper to skillet and cook, stirring frequently, for about 3-5 minutes or until onions are translucent.
Add beef chuck to skillet and cook, stirring frequently, for about 5 to 7 minutes or until beef is cooked through.
Add tomato sauce to skillet and toss and cook with other ingredients for 1-2 minutes.
Remove skillet from heat and let cool slightly, about 10-15 minutes.
Add olives, hard boiled egg, oregano, paprika, cumin, salt, and pepper to skillet, then mix well.
When ready to assemble empanadas, lay out an empanada dough sheet and spoon prepared filling into the center. Lightly wet the edges of the empanada with water, then fold, using your fingers to press down and seal the empanada. For pretty presentation, press a fork around the edges of the empanada. Place empanada on prepared baking sheet. Repeat this step until all empanadas are assembled.