Preheat your oven to 425°F (220°C). Thoroughly wash the red potatoes and chop them into uniform ¾-inch cubes.
Spread the diced potatoes evenly over a baking sheet with raised edges. Drizzle with olive oil and gently toss to ensure each piece is coated. Season generously with sea salt and freshly ground black pepper. Roast in the preheated oven for 30–35 minutes, or until the potatoes are fork-tender and crisped to a golden hue. Let them cool to room temperature once removed from the oven.
In a mixing bowl, stir together the mayonnaise, sour cream, and apple cider vinegar until the dressing is smooth and well-blended.
Transfer the cooled potatoes to a large mixing bowl. Add the dressing, shredded cheddar, crumbled bacon, and sliced green onions. Fold gently to combine until all components are evenly coated.
Refrigerate the salad for at least 30 minutes prior to serving to allow the flavors to meld thoroughly. Taste and adjust seasoning with additional salt and pepper, if needed.