Spray a non stick skillet with non-stick spray and heat.
Place tilapia in the skillet and sprinkle with onion powder, cracked pepper, and sea salt and grill. Grill on each side for about 5 minutes, and after flipping the first time, sprinkle the opposite side with onion powder, garlic powder, cracked pepper, and sea salt. To test doneness, ensure that fish flakes easily.
Wile tilapia is cooking, combine coleslaw mix, dressing, and crushed pineapple in a medium sized bowl. Mix until combined.
Top half of whole wheat hamburger bun with one cooked tilapia filet, and 1/4th prepared pineapple coleslaw and other half of hamburger.