Cook potato and salt in a Dutch oven in boiling water to cover 20 minutes or until tender; drain. Mash potato, and set aside.
Cook leeks in Dutch oven in boiling water to cover 3 minutes; drain.
Stir together potato, leeks, and next 5 ingredients. Chill 1 hour. Shape mixture into 18 patties.
Cook, in batches, in hot oil in a large skillet 2 minutes on each side or until golden brown. Serve immediately with sour cream, if desired.