In a bowl or zip-top bag, whisk together all marinade ingredients. Add chicken pieces and toss to coat. Marinate in the fridge for at least 30 minutes (up to 24 hours for deeper flavour).
2 tbsp harissa paste, 1 tbsp Greek yogurt, 1 tbsp olive oil, 1 garlic clove, 1/2 lemon, ½ tsp smoked paprika, ⅛ tsp salt, 1 pinch pepper
Thread chicken, bell pepper, onion, and zucchini onto skewers, alternating pieces.
2 chicken breasts, 1 red onion, 1 red bell pepper, 1 small zucchini, Wooden or metal skewers
Grill method: Preheat grill to medium-high. Grill skewers 8–10 minutes, turning occasionally, until chicken is cooked through (internal temp 165°F).
Oven method: Preheat oven to 425°F. Place skewers on a baking sheet lined with parchment or foil. Bake for 15–18 minutes, flipping halfway, until chicken is golden and cooked through. Broil for the last 1–2 minutes for extra char.
Sprinkle with fresh parsley or cilantro, a squeeze of lemon juice, or a drizzle of Greek yogurt mixed with lemon juice and garlic.