In a bowl, whisk together 1.5 tbsp olive oil, smoked paprika, ground cumin, garlic powder, kosher salt, black pepper and 1 tbsp lemon juice. Add chicken and coat evenly. Marinate at room temperature for 15–20 minutes or refrigerate up to 2 hours.

Preheat grill or grill pan to medium-high (about 425°F / 220°C). Brush the grill grates or pan with 1 tsp olive oil to prevent sticking.

Grill chicken 4–6 minutes per side (depending on thickness) until internal temperature reaches 165°F (74°C) and juices run clear. Transfer to a cutting board and let rest 5 minutes before slicing thinly to fit the rolls.

Harissa aioli

In a small bowl, combine 1/2 cup mayonnaise, 1 tbsp harissa paste, 1/2 tbsp lemon juice, 1/2 tsp minced garlic and 1/2 tsp olive oil. Whisk until smooth.

Season with 1/4 tsp salt and 1/8 tsp black pepper. Taste and adjust heat by adding more harissa if desired. Chill while finishing other components so flavors meld.

Sandwich assembly & finishing

Split the ciabatta rolls and butter the cut sides lightly. Toast buttered cut sides on the grill or in a skillet until golden and crisp, about 1–2 minutes.

Spread a generous layer (about 1–1.5 tbsp) of harissa aioli on both cut sides of each toasted roll.

On the bottom half of each roll, spread half of the goat cheese (about 1.5 oz per sandwich) and gently smear to create an even layer that will help hold the chicken.

Arrange sliced grilled chicken over the goat cheese, dividing evenly between the two sandwiches.

Top the chicken with sliced pepperoncini (about 2 tbsp per sandwich) distributed evenly, then pile about 1 cup arugula per sandwich on top. If arugula seems dry, squeeze a little lemon juice over it.

Close sandwiches, press lightly, slice in half if desired, and serve with optional lemon wedge and extra harissa on the side.