Quarter the potatoes, with their skins. Boil them, until they are easily pierced with the tip of a knife (about 15 minutes). Drain potatoes, and transfer to a mixing bowl. Add the king crab meat, scallion, parsley, and lemon zest. Toss with a fork to combine. Mix in the oil and lemon juice to coat the potatoes. Season to taste with pepper. Serve crab salad mounded on a bed of shredded lettuce, surrounded by sliced cucumbers.