Lightly coat chicken thighs with olive oil and season with garlic powder, kosher salt, and black pepper. When the Blackstone is hot, add a little more olive oil and place the chicken on the griddle. Cook thoroughly, flipping occasionally.
While chicken is cooking, prepare the slaw. In a mixing bowl, combine half the bag of cabbage slaw with champagne vinegar, maple syrup, and Blackstone Island Stir Fry Seasoning. Mix well and set aside. Toss occasionally if made ahead.
Prepare the special sauce by mixing Dukes Mayo, sriracha, Island Stir Fry Seasoning, and pineapple juice to thin it out.
Slice pineapple into thin pieces. Add to the griddle alongside the chicken to caramelize and develop char.
When chicken is nearly done, turn off the heat and glaze with teriyaki sauce. Allow the sauce to thicken on the hot griddle. Toast burger buns if desired.
Build the sandwiches: Spread sauce on the bottom bun, top with chicken, caramelized pineapple, and slaw. Add more sauce to the top bun, then assemble and enjoy!
