Heat a large skillet over medium high heat. Season beef with black pepper and add to skillet. Cook, stirring and crumbling into small pieces with a wooden spoon, until browned. Drain excess grease. (Optional: put beef in a food processor. Pulse it 2-3 times into very small pieces, and then return it to the pan.)

Add sesame oil, garlic and ginger. Stir in brown sugar, soy sauce, and sriracha (or crushed red pepper of chili sauce). Cook for a few minutes, allowing some of the sauce to absorb into the meat.

Add half of the chopped green onions, reserving the rest for garnish. Serve over hot cooked rice, garnished with chopped green onion.