Dice the red potatoes into bite-sized pieces, drizzle with olive oil, and season with salt and pepper. Preheat your air fryer to 400°F and arrange potatoes in a single layer. Air fry for 16-18 minutes, shaking the basket halfway through.

Heat a skillet over medium-low heat and add olive oil. Toss in diced onions, cooking for about 10-15 minutes until golden brown and fragrant.

Increase skillet heat to medium-high, add ground beef, and press down to 'smash' it. Cook for 5-7 minutes until browned and crispy. Season with salt and pepper.

Mix mayonnaise, ketchup, mustard, and Cajun seasoning in a small bowl. Whisk until smooth, adjusting ingredients to taste.

Assemble the bowls with crispy air-fried potatoes at the bottom, topped with ground beef, caramelized onions, shredded cheese, and drizzle with sauce. Add any extras like pickles or lettuce.