In a large bowl, stir together yogurt, paprika, garlic, olive oil and salt. Add the chicken pieces to the bowl, and turn to coat with the yogurt mixture. Cover the bowl with plastic wrap and marinate in the fridge for 2-8 hours.
Preheat oven to 400°F Line a baking pan with cooking spray. Cut the potatoes in half, and lay them in the baking pan.
Place the chicken pieces on the potatoes. Roast for 45-60 minutes, or until chicken is done.