In
a small bowl, combine olive oil, lemon juice, oregano (if used),
parsley, 1 teaspoon salt and onion. Mix well and set aside.
Wash
potatoes well.
Add
potatoes to a large pot of boiling, lightly salted water. Cook potatoes
at low boil for about 15 - 20 minutes, or until potatoes are just
tender. Do not overcook.
Drain
water and let potatoes cool slightly to touch.
When
slightly cooled, peel and cut potatoes into slices or large dice (If
desired, leave skin on red potatoes).
Place
potatoes in a large bowl; add dressing and season with additional salt
and pepper to taste. Toss to coat.
Cover
bowl and refrigerate for several hours or overnight. Stir every once in
a while to redistribute dressing.