Marinate the Chicken: In a large bowl, combine the diced chicken with lemon juice, salt, olive oil, garlic, Italian seasoning, grated Pecorino Romano cheese, and breadcrumbs. Toss everything together until the chicken is evenly coated. Let it marinate for about 10 minutes.
Preheat the Air Fryer: Preheat your air fryer to 400°F (200°C) for about 3-5 minutes to ensure even cooking.
Coat the Chicken: Spray the air fryer basket with olive oil to prevent sticking. Arrange the breaded chicken in a single layer in the basket, making sure not to overcrowd the chicken pieces.
Air Fry the Chicken: Air fry at 400°F for 7 to 8 minutes. At the halfway mark (around 3-4 minutes), shake the basket or use tongs to turn the chicken pieces over. Lightly spray the chicken with more oil and continue air frying for the remaining time. The chicken is done when it is golden brown and the internal temperature reaches 165°F.
Prepare the Salad (Optional): While the chicken is cooking, prepare the salad. In a small bowl, combine the chopped red onion with garlic, olive oil, red wine vinegar, salt, and pepper. Let it sit for 5-8 minutes to allow the flavors to meld. Add the diced cucumbers and avocado, and toss everything together.
Serve: Once the chicken is cooked, serve it alongside the salad, or you can top the chicken with the fresh salad.