Heat oil in a large skillet over medium-high heat. Add diced onion, white parts of the green onions, and garlic. Saute until onions are translucent and garlic is fragrant, about 5 minutes. Add ground beef, sriracha, ginger, salt, and black pepper. Saute until beef is browned and crumbly, about 5 minutes.

Stir coleslaw mix, soy sauce, and cider vinegar into the beef mixture. Saute until coleslaw is tender, about 4 minutes more. Top with the rest of the green onions.