Separate the chicken legs and thighs and place in a large bowl
Add the olive oil and Greek seasoning and toss to coat
Heat a large heavy skillet sprayed with cooking spray on medium high heat and place the chicken pieces skin side down until the skin is nicely brown, turn and repeat on the second side, 8 to 10 minutes.
Place the browned chicken in a slow cooker.
Using the same skillet, on medium heat, add the onion and peppers to soften, 5 minutes.
Stir in the chicken broth, tomato sauce, yogurt dressing and the pepper flakes and bring to a boil then pour this over the chicken in the slow cooker.
Cook on high heat for 2 hours.
Next, add the orzo and kalamata olives, stir in and cook for 35 to 40 minutes more until the orzo is done.
Remove the chicken parts and place on a large platter or shallow serving bowl, then stir in the spinach leaves to wilt, about 2 minutes.
Pour the orzo/spinach/kalamata olive mixture into the serving dish with the chicken.
Serve right away.