Preheat the grill until hot. Place one slice of prosciutto onto a baking sheet and place under the grill for 2-3 minutes, or until crisp. Remove from the grill and set aside. Finely chop the remaining slice of prosciutto and set aside.
Arrange the tomato slices on a serving plate and top with the rocket.
Place the remaining ingredients and the chopped prosciutto into a small bowl and whisk until combined.
To serve, pour the dressing over the salad on the serving plate and top with the crisp prosciutto.