"Who wants bulgogi?"
Translation:누가 불고기를 원해요?
누구 and 누가 are both "who." 누군가 would be "someone." The difference between the first two is simply that 누가 means "who" is the sentence's subject, so you're right it could be loosely translated as "anyone want bulgogi?"
That said, I might be inclined to say "불고기 먹고 싶은 사람?" instead. I hear this kind of phrasing at work all the time.