In a small bowl whisk the vinegar, shallot, mustard, sugar, salt, and pepper. Gradually drizzle in both oils, whisking constantly, until emulsified. Taste, and if the vinaigrette is too tart, add 1 tablespoon or so of water.
Prepare the grill for direct cooking over medium heat (180° to 230°C).
Prepare the grill for cooking over medium heat (200°C).
Wrap a slice of prosciutto around each pear wedge, pressing the loose ends of the prosciutto down so the meat stays together. Brush the cooking grates clean. Lightly brush the outside of the wrapped pears with some vinaigrette and grill them over direct medium heat, with the grill lid open, until the prosciutto is slightly crispy and golden brown and the pears are warm, 4 to 6 minutes, turning as needed.
Wrap a slice of prosciutto around each pear wedge, pressing the loose ends of the prosciutto down so the meat stays together. Brush the cooking grates clean. Lightly brush the outside of the wrapped pears with some vinaigrette and grill them over medium heat, with the grill lid open, until the prosciutto is slightly crispy and golden brown and the pears are warm, 4 to 6 minutes, turning as needed.
Whisk the vinaigrette again to emulsify the ingredients. In a large bowl, toss the arugula with enough vinaigrette to lightly coat the leaves (you may not need all the vinaigrette) and divide among four salad plates. Top each salad with two warm pear wedges and drizzle with some additional vinaigrette. Using a swivel vegetable peeler, shave wide ribbons of cheese over each salad, and then sprinkle with the hazelnuts. Season with salt and pepper. Serve immediately.
