Slice the sausage into ½-inch thick rounds. Chop the onions and bell peppers into 1-inch pieces.
Place the sausage and vegetables in a large bowl. Drizzle the cooking oil over top. Combine the smoked paprika, garlic powder, salt, and pepper in a small bowl, then sprinkle over the sausage and vegetables.
Toss the sausage and vegetables until well coated in oil and spices.
Build the kebabs by skewering the sausage and vegetables in an alternating sequence. You should get about eight kebabs, depending on the size of your skewers and vegetables.
Cook the kebabs over a hot grill, on a hot cast iron grill pan (preheated well over medium-high heat), or under your oven's broiler (about 5-6 inches from the broiler) until the kebabs are slightly charred on one side.
Flip the kebabs and continue to cook until charred on a second side. Brush a light coating of BBQ sauce over the side that has already been charred. Continue to cook, turn, and brush on BBQ sauce until the kebabs are charred on all sides and the BBQ sauce is slightly caramelized. Serve hot and enjoy!