Use a chef's knife and cutting board to carefully chop the ripe watermelon into bite-sized chunks, ensuring even pieces for texture and visual appeal.
Place the diced watermelon into a large mixing bowl. Add finely chopped fresh mint leaves and red chili, distributing evenly throughout the watermelon.
Gently toss the mixture with a spoon until all ingredients are evenly coated with mint and chili, ensuring the flavors are well integrated.
Let the salsa sit at room temperature for 5 minutes to allow the flavors to meld and the chili to infuse into the watermelon.
Serve the watermelon salsa in a shallow bowl or on a plate, garnished with additional mint leaves if desired, showcasing the chunky, colorful mixture.