Place beef on a cutting board, and cut into uniform 1 ½-inch pieces. Season beef directly on the cutting board; sprinkle with salt and 2 tablespoons flour, and toss until thoroughly and evenly coated.

Add vegetable oil to a heavy bottomed stew pot, and set over high heat. Working in 2 or 3 batches so that beef is in a single, uncrowded layer, brown beef pieces deeply on at least 2 sides; transfer into a bowl and set aside. Reduce heat to medium-high if beef is browning too quickly or pan seems too hot.

Remove the last batch of browned beef to the bowl, reduce heat to medium-high, and transfer in onions. Cook, stirring for a few minutes until they just start to turn translucent. Add tomato paste, and cook and stir until tomato paste begins to brown on the edges of onion, about 4 minutes.

Sprinkle in remaining 2 tablespoons flour, and cook, stirring, for about 2 minutes. Transfer in tomato sauce and beef broth, and stir to combine. Add Worcestershire sauce and soy sauce, and bring stew to a boil, stirring occasionally.

Return browned beef pieces and all accumulated juices to the pot and stir to combine. Reduce heat to low. Cover tightly, and simmer gently for 1 hour.

Uncover, and stir in black pepper, cayenne, carrots, celery, and potatoes. Cover again and simmer on low for 1 hour.

Remove the lid, and simmer uncovered until sauce reduces slightly and thickens, and meat is very tender, about 1 hour more. Taste for seasoning and adjust if need be. Serve with rice.