Light your charcoal in the KUDU and let them burn to embers with a layer of white ash.
While the charcoal is prepping prepare your watermelon and pineapple by cutting them into slices roughly 1/2 inch - 1 inch thick.
Drizzle a little olive oil and salt and pepper over the fruit.
Adjust your grill height over the embers at medium-heat. To locate medium-heat, place your hand over the embers and find the height you can count to 3 or 4 before having to remove your hand (approx. 500 degrees).
Move your KUDU grill grate to that height and place your fruit on the grill.
Rotate your fruit on all sides until sufficiently cooked with light grill marks on both sides.
Remove and serve.