Cut the red onions into 1-inch squares. Place the red onion in a bowl, drizzle with 1 Tbsp cooking oil, and toss to coat.
Cut the pineapple into 1-inch cubes.
Cut the chicken breast into 1-inch cubes, then place the chicken pieces in a bowl. Drizzle 1 Tbsp cooking oil on top, then add the smoked paprika, sweet paprika, garlic powder, salt, and pepper. Toss the chicken until it is well coated in oil and spices.
Build your kebabs by adding pineapple, onion, and chicken to skewers, alternating as you go. I got ten skewers, but the yield will vary depending on the length of your skewers and size of your pieces.
Heat a grill or grill pan over medium. Once hot, add the kebabs and cook for a few minutes on each side.
When the kebabs are almost cooked through, brush them on all sides with BBQ Sauce. Cook the chicken kebabs for a minute or two more on each side, or until the chicken is cooked through and the BBQ sauce is slightly caramelized.
Sprinkle the sliced green onions over top just before serving.