The first officer, seated in the left seat for the purpose of nose wheel steering familiarization, and the captain, seated in the right seat, reported that the purpose of the flight was to reposition the airplane from Kona, Hawaii to Honolulu, Hawaii. The first officer reported that, while on approach to Honolulu, he called for flaps and gear down. Simultaneously, Honolulu tower requested them to, “slow down to slowest practical speed”. The pilots became distracted while initiating the reduction in airspeed and forgot to monitor the status of the landing gear. The captain reported that he did not verify that the gear was down. The airplane was equipped with tricycle landing gear featuring a fully retractable nose gear and partially retractable main gear. The pilots reported hearing the gear warning horn during the flare, at which time they glanced in and confirmed that the landing gear was retracted. The airplane landed gear up and the forward bottom section of the fuselage contacted the runway surface, which resulted in substantial damage to the fuselage. The pilots reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. A postaccident operational check of the airplane’s landing gear revealed no anomalies.