Place a cutting board on a stable surface and use a sharp chef's knife to cut the watermelon into 1-inch cubes, removing any seeds if present. Transfer the cubes to a large mixing bowl.
Repeat the process with the fresh pineapple, cutting into 1-inch cubes similar in size to the watermelon pieces, then add to the bowl with the watermelon.
Gently toss the chopped watermelon and pineapple together using a large spoon or spatula, ensuring an even distribution of the fruits.
Sprinkle a light pinch of salt over the fruit mixture if desired, then give it a gentle stir to combine the flavors evenly.
2 cups watermelon
Serve the fruit salad immediately, showcasing the vibrant colors and crisp textures of the fruit, or chill briefly before serving for a more refreshing experience.