Heat oven to 375°F. In 10-inch skillet, mix cooked beef and ketchup. Heat over medium-high heat, stirring occasionally, until hot. Stir in relish, cheese and mustard. Set aside. Separate dough into 4 rectangles. Place on ungreased cookie sheet. Press each to 8x5 inches, firmly pressing perforations to seal.
Divide beef mixture evenly among rectangles. Bring ends up over filling, overlapping about 1 inch. Press edges with fork to seal. Brush each with water, and sprinkle with 1/4 teaspoon sesame seed.
Bake 13 to 15 minutes or until golden brown. Immediately remove from cookie sheet. Serve warm.