Preheat your grill to 450 degrees F.
Season the flank steak on both sides with the Himalayan salt. Don't rub in. Set aside while you prepare the rest of your ingredients.
Place the pineapple skewers in a gallon bag with the brown sugar and gently massage to coat all sides of the pineapple with the sugar.
Open the grill and place the flank steak, pineapple skewers, and pepper rings directly on the grill grates. Close the lid and cook for 5 minutes. Open the lid and turn over the steak, peppers, and pineapple. Close the lid and cook for an additional 5 minutes.
Remove the pineapple and bell peppers to a cutting board. Rough chop them together and transfer to a medium bowl. Gently stir in the cilantro, garlic, lime juice, and salt. Set aside until you are ready to serve.
Test the steak for the correct internal temperature using a meat thermometer. The temperature should read 125 degrees F for rare, 130-135 for medium rare, 140 for medium, 150 for medium well, or 155 for well done. Pick up the steak and give it a little smack with the back side of your knife to shake off any excess salt and transfer it to a cutting board. Let the steak rest for 4-5 minutes before slicing thinly against the grain.
Transfer the steak to a serving platter (or serve directly from the cutting board) and top liberally with the grilled pineapple salsa. Enjoy!!