"Wanafunzi walikuja wakicheza"
Translation:The Pupils came playing
Sometimes the word "huku" is used to clarify or emphasize the participle. But I think it's correct to say that "huku" tends to be used in longer sentences and carries the meaning of "while" : Mzee alicheka chini chini huku akifikiria jinsi atakavyowadanganya wajinga hao. "The old man chuckled (to himself) while (he was) thinking how he would trick these fools."
That said, there would be nothing wrong that I can see with saying: Wanafunzi walikuja, huku wakicheza
Glosbe.com: Alisema [maneno machache], huku machozi yakimlenga machoni -- He said a few words, while tears were falling from his eyes.*