Combine the minced shallot with the raspberry vinegar, the orange zest, half the orange juice, and a pinch of salt. Set aside. Halve the nectarines, remove the pits, and then slice the halves into 1/4-inch wedges; toss them with the remaining orange juice and set aside. Gradually whisk the olive oil into the shallot and vinegar mixture and add a few grinds of black pepper. In a small bowl, very lightly mash the raspberries, allowing them to keep some of their original shape and then stir them gently into the vinaigrette. Just before serving, put the arugula in a large bowl and toss with half the dressing to coat the leaves lightly. Toss the nectarines in 1 tablespoon of the vinaigrette. Arrange the arrugula on a platter or individual serving dishes, topping the greens with the nectarine slices. Drizzle with a bit more dressing and serve.