In a bowl, mix olive oil, lemon juice, minced garlic, oregano, cumin, salt, and pepper.
Add cubed chicken and toss to coat. Cover and marinate in the fridge for at least 1 hour (up to 4 hours for best flavor).
Preheat your grill or grill pan to medium-high heat. Thread marinated chicken onto skewers.
Grill for 10-15 minutes, turning occasionally, until the chicken is fully cooked and has a nice char (internal temperature should reach 165°F or 74°C).
Serve the chicken skewers hot with a side of tzatziki sauce, pita bread, and a simple salad of cucumbers, tomatoes, and red onions. Optionally, drizzle extra lemon juice over the top for brightness.
