Put the potatoes in a large saucepan; cover with water. Bring to a boil. Reduce heat, and simmer 12 minutes or until tender; drain. Put potatoes in a large bowl. Add 2 tablespoons white wine vinegar, and toss gently. Cool completely. Chop egg whites (do not need yolks); set aside. Combine remaining 2 teaspoons vinegar, mayonnaise, sour cream, buttermilk, mustard, black pepper, and kosher salt in a small bowl; stir with a whisk. Add in vinegar mixture, egg whites, red onion, red bell pepper, sweet pickles, green onion, and sugar snap peas to potato mixture, stirring gently to coat. Allow to chill before serving