1. In a blender, combine cilantro, mint leaves, yogurt, lemon juice, ginger paste, garlic paste, cumin powder, coriander powder, and salt. Blend until smooth.
2. In a mixing bowl, add the chicken cubes and pour the green herb mixture over them. Mix well to coat the chicken evenly. Marinate for at least 1 hour.
3. Preheat the grill to medium-high heat. Thread the marinated chicken onto skewers.
4. Grill the chicken for about 10-15 minutes, turning occasionally, until fully cooked and slightly charred.