The classic sweet-salty pairing of prosciutto and melon inspires this summery salad.
Cut the melon in half and discard the seeds. Using a melon baller, remove the flesh in neat balls, or alternately, cut the fruit into 3/4-inch cubes (discard the rind).
Place the oil and vinegar in a medium-size bowl and whisk to combine. Add the arugula and toss to coat the greens. Divide the arugula among 4 chilled salad plates. Garnish each serving with melon balls, ribbons of prosciutto, and a scattering of pine nuts. Season to taste with salt and pepper.