Cut each pear half into 3 slices lengthways. Brush or drizzle with a little of the olive oil and grill for 2-3 minutes until the slices are heated through and are lightly browned. Remove from the grill and set aside.
Brush the bread slices with the remaining oil.
Place the bread slices on serving plates and top each with 2 slices of Parma ham and 3 pear slices. Finally, crumble over the blue cheese and season with freshly ground black pepper and cherry tomato halves.
Toss the salad leaves with the vinaigrette dressing and serve with the crostini.