Cut the tomatoes into irregular wedges, removing the tough core. Put them in a wide, shallow bowl and sprinkle with the salt.
Halve the cucumber lengthwise and cut it into thick half-moons. If the skin is waxy, peel it in stripes first.
Seed the pepper and slice it into thin rings. Slice the onion as thinly as you can and separate the layers.
Add the cucumber, pepper, onion, olives and capers to the tomatoes and toss gently with your hands.
Drizzle with the vinegar and most of the olive oil and toss once more. Let the salad sit for 5 minutes so the tomatoes start to release their juices.
Lay the block of feta on top, sprinkle with the oregano, drizzle the rest of the oil over the cheese and serve with bread.