Grilling peaches is a snap, and they add a nice tart-sweet accent to salads. This salad combines several elements for a perfect balance of flavors: nutty arugula with its hint of pepper...creamy, pungent Roquefort...sweet peaches. If you like prosciutto, its salty flavor is another great addition to this salad.
Cut the peaches in half through the stem end and discard the pits. Brush all surfaces of the peaches with the olive oil and sprinkle with salt and pepper. Grill the peaches over a medium fire until they brown lightly and begin to soften slightly, 4 to 6 minutes on each side. Transfer the peaches to a platter and let them cool. When cool, cut each half into 1/2-inch-thick wedges.
Place the arugula in a large salad bowl. Combine the vinegar and oil in a glass jar and add a pinch of salt and a few grinds of pepper. Shake vigorously to combine. Toss the arugula with the vinaigrette and then divide the greens among 4 salad plates. Top each salad with a sprinkling of cheese and pecans, then arrange 3 or 4 grilled peach wedges atop the greens. Serve immediately.