Rub Salt And Cayenne Into Fish. Dust With Flour. Saute Fish In Oil Until Browned On Both Sides. Remove And Set Aside. Saute Onion In Same Pan For 5 Minutes. Add Tomatoes And Tomato Paste. Simmer For 10 Minutes. Add Water If Necessary To Make A Thinner Gravy. Add Fish To Pan, Reheat For 5 Minutes. Serve Fish Covered With Tomato Gravy.