Boil fingerling potatoes in lightly salted water until tender, about 12 to 15 minutes. Drain and cut larger potatoes into bite size pieces.
Add butter, salt and pepper. Mix well with boiled potatoes.
Add vegenaise or mayonnaise and lemon juice. Toss to get potatoes evenly coated.
Chill in the refrigerator for 2 hours.
Sprinkle bacon and green onions on top before serving.