Step 1Peel potatoes and dice. Rinse in cold running water. Bring large pot of salted water to rolling boil, drop in diced potatoes and boil until tender, 8 to 10 minutes. Drain in colander and transfer to shallow dish to cool.
Step 2Add carrot, fennel, red bell pepper, corn kernels, parsley, mayonnaise to moisten, and salt and pepper to taste.
Step 3Place a 3- or 4-inch ring mold on serving plate and spoon in salad mixture. Trim salmon slices to fit mold. Arrange slice of smoked salmon on top of salad. Repeat with remaining 7 serving plates. Spoon about 1 tablespoon Mustard-Dill Sauce around each serving. Garnish with dill sprigs.