Cut the onions into small wedges.
Heat the grapeseed oil in a saucepan over medium heat.
Sauté the onions in the saucepan for 2 minutes.
Add the chicken pieces and brown for 5 minutes, turning frequently.
Add the tomatoes, stock, and paprika to the saucepan.
Cook over medium heat for 30-40 minutes or until chicken is soft and falling off the bone.
If necessary, add more stock to maintain a sauce.
Serve chicken pieces with sauce over rice.