Toss the potatoes with 10 tablespoons of vegetable oil; sprinkle with paprika and dill. Toss until the potatoes are evenly coated with the spices and spread onto a baking sheet. Bake in the preheated oven until the potatoes are easily pierced with a fork, about 25 minutes.
While the potatoes are roasting, heat the 2 tablespoons of vegetable oil in a large skillet over medium heat. Stir in the banana pepper, bell pepper, celery, and onion; cook and stir until the vegetables have softened, about 10 minutes. Toss the pepper mixture with the roasted potatoes in a bowl. Refrigerate until cold, about 1 hour.
While the potatoes are cooling, whisk together the red wine vinegar, olive oil, and kosher salt. Toss the potatoes with the salad dressing just before serving.
