Luciano Fabbri is the Cuneo Consigliere. Although there is an unsteady truce between the Cuneos and Corleones, Luciano has been longing for a war. He is an influential voice in the Cuneo ranks, so take out Luciano before he can cause trouble.
Approach Fabbri and his men from the east, on 42nd St. Crouch down and hide behind any parked cars you can find. When you're close enough, start killing his men as quickly as you can. Then shoot him in the knee.
Go up and talk to him. You will tell him that he should have hired better bodyguards. This will fulfill the taunting bonus condition. You may now kill him.