Pat the chicken thighs dry with a paper towel.
In a medium bowl, whisk together the spices and seasonings, including the salt, pepper, smoked paprika, garlic powder, celery salt, onion powder, and brown sugar.
Toss the thighs in the bowl with the spice mix 'til the chicken is coated.
Heat the olive oil in a large skillet over medium heat.
Sear the chicken in the hot skillet over medium heat, cooking 2-3 minutes per side.
Place the seared chicken immediately into the greased slow cooker, and pour the apple cider vinegar and Worcestershire sauce around the chicken, not over it; that way, you don't wash the seasonings off the chicken.
Cover and slow cook on low for 4-6 hours, 'til the chicken is cooked all the way thru.
Once the chicken is fully cooked, remove the meat to a large mixing bowl, and shred it with forks.
Mix about 1/4 cup of the leftover liquid from the slow cooker back into the shredded chicken; then remove the rest of the liquid from the slow cooker and either set aside to save or dispose of it.
Add the bbq sauce to the chicken and mix together well.
Place the bbq chicken mixture back into the slow cooker; then cover and cook on low for about 45 minutes.
When you're ready to assemble the sliders, slice the Hawaiian Rolls in half, as a whole. You’ll have the top layer of the rolls, and then a bottom layer. Place the bottom layer of the rolls in a lightly greased baking dish or baking sheet.
Spread the bottoms of the rolls with mayo.
Using tongs, pile on the bbq chicken.
Lay the provolone cheese on top of the chicken.
Now add the top layer of rolls.
In a separate small bowl or glass measuring cup, mix together the melted butter, garlic powder, and minced parsley.
Brush the tops of the rolls with the garlic butter mixture, and sprinkle with extra Italian parsley if desired.
Bake at 350° F for about 10 minutes, or 'til the cheese is melted and the buns are golden.
And that's it! Serve while warm and enjoy!*