Drain the melon in the fridge. Watermelon cell walls bleed the moment you cut them. Fifteen minutes in a colander sheds the surface juice so the vinaigrette clings to the fruit instead of sliding off it into a pink pool.
Two temperatures on purpose. Ice-cold watermelon keeps its cell walls rigid and its crunch. Room-temperature tomatoes keep the volatile aromatic compounds that refrigeration destroys. The contrast is the dish.
Break the feta by hand. Pre-crumbled feta turns to a muddy paste the moment it is tossed. Hand-broken brine-packed sheep's milk feta gives you distinct bursts of salt against the sweet fruit.
