My favorite potato salad is from this little deli right around the corner from our old place in San Francisco. You put the onions and parsley into the food processor or blender so it doesn't end up tasting too onion-y.
4 large potatoes, boiled until soft but firm
1/2 Mayer Lemon
1/4 c onions chopped finely in the food processor
2 tbsps olive oil
2 eggs, harboiled
Once potato is cooled, slice as you would lemon rounds. Add jiuce of 1/2 a lemon. Add the onions, parsley, salt and pepper. Toss trying as much as you can not to mash the potatoes. Add just enough mayonnaise to coat the potatoes. Add about 2 tbsps olive oil. Taste and season accordingly adding more salt or pepper.
Top with the hardboiled eggs. Serve cold. Mmmm good.