Make the Cucumber Apple Salad: Combine cucumber and apple in a bowl. Toss with lemon juice, avocado oil, garlic powder, salt, and crushed red pepper. Set aside to lightly marinate.
Make the Yogurt Herb Spread: Mix Greek yogurt, parsley, and a pinch of salt until smooth. Set aside.
Bread the Chicken: Season chicken lightly with salt. Dredge in flour, shaking off excess. Dip into beaten egg. Press firmly into crushed cornflakes until fully coated.
Air Fry the Chicken: Preheat air fryer to 385°F. Lightly spray chicken with avocado oil. Air fry for 12 minutes, flipping halfway, until golden, crispy, and cooked through. Rest for 2 minutes to set the crust.
Make the Sauce: In a small pan over medium-low heat, melt butter with avocado oil. Add chopped garlic and cook for 30 seconds, just until fragrant. Stir in maple syrup and honey. Simmer gently for 2–3 minutes, stirring constantly. Finish with a pinch of salt and crushed red pepper. Sauce should be glossy and sticky, not thick.
Sauce the Chicken: Transfer hot chicken directly into the sauce pan and dredge it in the sauce, turning to coat evenly. Remove and let excess sauce drip off.
Assemble the Sandwich: Toasted ciabatta baguette. Spread yogurt herb mixture on both bread slices. Sauced chicken. Cucumber apple salad. Extra sauce spooned on top. Top baguette.