Preheat oven to 200 C (400F). This is to brown your chicken once it has boiled.
Heat the oil over medium high heat in a large saucepan. If using potatoes, add them now and cook for 3-5 minutes, then add the onions and grated ginger. Cook until light golden brown.
Add the chicken pieces, and cook till lightly browned. Add the spices (salt, pepper, orange zest, cardamom, cumin, coriander, cinnamon, cloves or clove powder, loumi, and add the tomato paste and diced or canned tomatoes. Let this come to a boil.
Once mixture boils, add 1 litre of water until chicken is submerged. Reduce heat to medium, cover and cook chicken for 25 minutes or so until cooked through, then remove just the chicken pieces to a baking pan, coat very lightly with oil and put in the oven. Roast for 20-25 minutes or until browned. You can turn on the ovens broil function for the last few minutes to brown even more. Keep the tomato stock mixture on the stove to make your rice with.