In a large bowl, combine the chicken, olive oil, paprika, cumin, coriander, cinnamon, garlic powder, salt and pepper. Toss to coat the chicken evenly. Cover and refrigerate for 30 minutes to 1 hour.
Preheat grill to medium-high heat.
Thread the marinated chicken onto skewers, leaving a small space between each piece.
Grill the chicken skewers for 8-10 minutes, turning occasionally, until cooked through and lightly charred.
Meanwhile, make the yogurt mint sauce by combining the yogurt, mint, lemon juice, garlic and salt in a small bowl. Stir to mix well.
Serve the grilled chicken skewers warm, with the yogurt mint sauce on the side for dipping. Garnish with extra chopped mint if desired.