Prepare the Dough : Combine flour and salt, rub in oil until crumbly, then add water gradually to form a firm dough. Cover and rest.
Prepare the Filling : Heat oil, sauté cumin seeds, onion, garlic, and ginger. Add ground beef and cook until browned. Stir in spices, potatoes, salt, and cilantro. Cook briefly and cool.
Shape the Samosas : Divide dough, roll into circles, cut in half, form cones, fill, and seal edges.
Fry the Samosas : Deep fry over medium heat until golden and crisp. Drain on paper towels.