Put the chicken legs in a pot and pour cold water over them. Cook until ready, while also adding the broth and paprika once they come to a boil.
Periodically remove the released foam. If, when you pierce the legs with a knife, a clear, colorless liquid comes out (not a bloody one), it means they're ready.
In the meantime, chop the onions finely and saute them with the oil in an oven dish in a preheated 428°F (220 °C) oven. Season with salt, black pepper and paprika. Add the potatoes, which you've cut into strips. Pour in hot water but don't cover them with it completely. Cook until they begin to soften.
Grate the tomatoes without their skins and add them, along with the finely chopped parsley. Strain the legs and put them in with the potatoes.
Cook until the legs are fully crisped and the potatoes boiled.