In a bowl, mix light mayonnaise, garlic, lemon juice, Dijon mustard, paprika, crushed red pepper, fresh parsley, finely chopped onion, thyme, onion powder, garlic powder, salt, and pepper until fully combined.
Coat chicken thighs completely in the marinade, making sure herbs and onions stick to the surface. Marinate for at least 30 minutes, preferably 2 to 12 hours.
Preheat air fryer to 385°F. Cook chicken for 16 minutes, flipping halfway through, until internal temperature reaches 165°F.
In a bowl, combine cucumber, cabbage, dill, parsley, salt, crushed red pepper, Maggie sauce, red wine vinegar, and mayonnaise. Mix well and chill.
Toast ciabatta bread lightly. Spread reserved cowboy butter on both sides of the bread. Add chicken, spoon extra sauce over the top, then add cucumber salad. Finish with freshly chopped chives, close the sandwich, and serve immediately.
