Heat sesame oil in a large skillet over medium-high heat. Cook and stir ground beef and garlic in the hot skillet until browned and crumbly, 5 to 7 minutes. Combine soy sauce, coconut sugar, ginger, and black pepper in a bowl; whisk until well combined. Pour over ground beef; simmer until the sauce thickens, about 3 minutes. Serve over cauliflower rice. Sprinkle with green onions and sesame seeds.