Rinse potatoes, cut diagonally into slices, brush lightly with oil and place on a baking sheet. Cook under a preheated oven broiler, watching carefully, for about 8 minutes. Rinse lemon with hot water, pat dry and finely grate zest. Mix lemon zest in a bowl with coarsely ground pepper, a little salt and sweet paprika. Remove potatoes from the oven, sprinkle with lemon zest mixture and serve immediately on plates.