Wash the rice under cold water until the water runs clear. Set aside.
Cook vegetables: Chop the onion finely, set it aside. Heat the oil in a large, heavy pan. Cook the onion and a pinch of salt for about 5 minutes until they soften.
In the meantime, finely chop the garlic and dice the green pepper. Add them to the pan and continue cooking for about 3 minutes, stirring regularly. In the meantime, chop the tomatoes.
Simmer: Add rice, turmeric, smoked and sweet paprika, red chili flakes to the pan. Stir well for about 2 minutes. Add tomatoes, salt, and chicken stock. Stir well to combine. Bring to a boil. Put the lid on, turn down the heat and simmer rice for about 10 minutes or until done.
Finish: Stir in lemon juice and adjust the taste with more salt if necessary. Fluff with a fork and sprinkle with chopped parsley or cilantro before serving.
Notes
If using table salt, take less. When salting, regard how salty the chicken stock is; some brands are saltier than others.