Question: how to cook pre cooked kielbasa?
Answer: Grill: Place kielbasa on a hot grill for 4-6 minutes, then flip and cook the other side for 4-6 minutes. ... 
Roast: Place kielbasa on tray in a 350° oven for about 20 minutes, turning frequently.
Sautée: Cut kielbasa into 1” thick slices and pan fry it with oil and sliced onions.