How to Make It
In a large saucepan, cover the eggs with lukewarm water and bring to a boil over high heat. Boil vigorously for 2 minutes. Cover, remove from the heat and let stand for 12 minutes. Drain the eggs and cool under running water, shaking the pan to crack the shells. When cool enough to handle, peel the eggs. Refrigerate until cold.
Put the potatoes in a large pot and add lukewarm water to cover. Add 3 tablespoons of salt and bring to a boil over high heat. Cook until the potatoes are completely tender but not falling apart, about 25 minutes. Drain the potatoes and spread them out on a large baking sheet to cool slightly. Peel the potatoes while they are still warm; let cool.
In a medium bowl, whisk the mayonnaise with the evaporated milk, mustard, vinegar, sugar and a generous pinch each of salt and pepper.
Thinly slice the eggs crosswise and transfer to a large bowl. Cut the potatoes into 1-inch chunks. In a large bowl, gently mix one-third of the eggs, potatoes, onion and celery with one-third of the dressing. Season with salt and pepper and transfer to a serving bowl. Repeat with the remaining ingredients in two more batches. Sprinkle with paprika and chives.