Prepare the watermelon by cutting it into 1-inch cubes on the cutting board using the chef's knife. Ensure the pieces are evenly sized for uniform texture and presentation.
Transfer the watermelon cubes into a large bowl, spreading them out evenly. Crumble the feta cheese over the watermelon, distributing it evenly across the surface.
Roughly chop the fresh mint leaves with the chef's knife, releasing their aroma. Sprinkle the chopped mint over the combined watermelon and feta.
If desired, drizzle the olive oil over the salad for added richness. Gently toss all ingredients together using a large spoon until evenly coated and combined.
Transfer the finished salad onto a serving platter, arranging the ingredients attractively to display the vibrant colors and contrasting textures.