This salad adds a spicy richness to lean, sweet watermelon. Sprinkling the melon with salt and sugar for 20 minutes draws out excess liquid to concentrate the melon’s flavor; it also seasons the melon cubes beyond their surface. And as a bonus, the salty-sweet liquid that drains out of them does double duty for removing the raw harshness of the jalapeño chiles that get soaked in it. If you want a less spicy dressing, remove the seeds from the chile before adding the slices to the blender. Similarly, if you want a less spicy salad, omit the remaining chile slices added at the end. If you want to use a mortar and pestle to make the dressing, grind the spices first, then crush the chile slices and garlic until smooth, before finally whisking in the rest of the ingredients.