Cut chicken into fairly large chunks. Soak chicken in yogurt mixture, turning to coat all parts. Let sit in fridge in yogurt marinade for and hour or so.
Preheat broiler. Place chicken pieces on a lightly oiled baking sheet(or line with tinfoil). Broil for 5 minutes. Turn pieces over and add tomatoes. Broil another 5 minutes. (The pan should be at least 10 inches from broiler).
Put spinach into saucepan with 1/4 cup boiling water. Cover tightly and let steam for 3 minutes. Drain.
Serve chicken and tomatoes on a bed of spinach. This dish goes well wth just about any grain. I served kasha (buckwheat groats with it).