Heat oil in a pan then add the onions with the salt and sauté until a glassy / translucent look for about 3-5 minutes while stirring frequently.
Add garlic and black pepper and saute until the garlic gets fragrant. The garlic can now be removed if desired.
Mix in the meat and stir-fry it until at least one side of the meat gets some golden brown color.
Sprinkle in paprika and add tomato.
Pour water into the pan until its content is half submerged in case of cuts with bones like drumsticks, tights, wings or the carcass. Chicken breast or other boned parts only need about a quarter cup of water. Put the lid on, bring the water to boil then reduce the heat and simmer for about 20 minutes in case of parts with bones and only 10 for boned ones.
Take the lid off then increase the heat to medium and cook away about half of the added water to get a somewhat thick tomato and onion enriched sauce. This takes about 20 minutes more for whole parts and approximately 10 for boneless cuts. Take it off heat and let the flavors come together for about another 10 more minutes. Serve it with sour cream.