In a cast iron pan, heat olive oil and sauté chopped onions and minced garlic for about 3 minutes, until the onion becomes translucent.
Season the chicken thighs with a pinch of salt and black pepper.
Place the chicken thighs, skin side down, into the pan and sear them for approximately 5 minutes. Flip them over and cook for another 5 minutes until they achieve a golden hue.
Add the canned tomatoes and water to the pan. Reduce the heat and let the sauce simmer gently for around 40 minutes, stirring occasionally. As it simmers, the chicken will tenderize and separate from the bones.
Adjust the seasoning with more salt and pepper if necessary.
To serve, remove the chicken skin and bones. This sauce is the perfect accompaniment for 4 servings of pasta.