In a mixing bowl, combine the yogurt, olive oil, lemon juice, garlic, cumin, salt and pepper. Add the cubed chicken and toss to coat with the marinade. (Make sure each cubes is well coated!) Let the chicken marinate for 20 minutes at room temperature.
Meanwhile, prep the salsa. Combine all the ingredients in medium mixing bowl. Season with salt and pepper. Cover and refrigerate for at least 10 minutes to allow the flavors to mingle.
Pre-heat a grill (or grill pan) over medium heat.
Thread the marinated chicken cubes onto skewers. (I recommend 4 cubes per skewer.) Cook for about 8 minutes, turning the skewers once halfway through, until the chicken is cooked through (aka no longer pink in the center).
Serve the skewers topped with salsa and crumbled feta.