Take 1 cup of the reserved pear juice and add it to a container with a tight-fitting lid, along with the oil, lemon juice, mustard, salt, ginger and pepper. Attach the lid securely and shake well to emulsify. Chill until ready to use. (The dressing will keep up to 2 weeks in the refrigerator.)
Tear the spinach and romaine leaves into bite-sized pieces. Just before serving, vigorously shake the dressing and pour it over the greens, tossing well to coat all of the pieces.
To serve, mound 2 cups of dressed greens each on 24 chilled plates. Garnish each salad with about 10 pear slices, 2 ounces of ham, 6 red pepper strips and 3 olives. Sprinkle each salad with 2 tablespoons diced red onion, 1 tablespoon crumbled blue cheese, and 1 tablespoon hazelnuts.