Step 1 Preheat oven to 180°C. Line a large baking tray with baking paper. Combine cumin, paprika, chilli flakes, half of the lemon juice and 1 teaspoon of the olive oil in a shallow glass or ceramic dish. Add chicken and stir to combine. Cover dish and leave to marinate for 15 minutes.
Step 2 Meanwhile, place sweet-potato wedges on prepared baking tray and spray with olive oil; roast, turning once, for 30–35 minutes, or until tender and golden.
Step 3 Meanwhile, thread marinated chicken onto skewers, alternating with onion wedges. Spray a large grill pan or barbecue hotplate with olive oil and heat to medium–high. Grill skewers, turning occasionally, for 6–8 minutes, or until chicken is cooked through.
Step 4 Place tomatoes, cucumbers, chickpeas and parsley in a large salad bowl with remaining lemon juice and olive oil; season with cracked black pepper and toss.
Step 5 Serve spicy chicken skewers with sweet potato wedges, and tomato and chickpea salad.