In a large pot of salted water, add potatoes and cook until just fork tender. Remove from boiling water and cool. When cool enough to handle, cut into 1-inch cubes.
While potatoes are cooking and cooling, fry bacon in a large nonstick frying pan, remove to paper towel lined plate to drain. Strain bacon fat, reserve 3 Tablespoons in pan.
Reheat bacon fat and fry off potatoes until light golden brown. Remove to paper towel lined plate to cool, season with a pinch of salt.
Combine sour cream, mayonnaise, white vinegar salt and pepper in a small bowl. Chop bacon and green onions. Combine potatoes and dressing, adjust seasoning as necessary. Refrigerate for 1 hour, top with bacon and green onions before service.