In a large mixing bowl, combine corned beef, sauerkraut, Swiss cheese, cream cheese, Dijon mustard, garlic powder, onion powder, and season with salt and pepper. Mix until fully combined and refrigerate for 30-45 minutes.

Once chilled, shape the mixture into balls, about 1 to 1.5 inches in diameter, and arrange on a parchment-lined sheet.

Set up a dredging station with flour, beaten eggs, and panko breadcrumbs in separate shallow bowls.

Coat each ball in flour, then dip in beaten egg, letting excess drip off, and finally coat with panko breadcrumbs, creating a crispy exterior.

Heat vegetable oil in a deep pot or fryer to 350°F (175°C).

Fry the breaded balls in batches for 2-3 minutes until golden brown, turning occasionally. Use a slotted spoon to remove and drain on paper towels.

For the dipping sauce, whisk together mayonnaise, ketchup, pickle relish, hot sauce, smoked paprika, Worcestershire sauce, and minced onion in a bowl until smooth. Adjust seasoning to taste.

Serve the crispy Reuben Balls hot with the Thousand Island dip.