Cut the artichoke hearts in quarters, place on paper towels to drain for 1/2 hour.
Cut the feta cheese in 1/2" cubes; slice the onion. Put them in a large bowl and set aside.
Make the dressing: Stir the vinegar, salt and garlic together. Add the oregano, pepper, basil and parsley; then slowly beat in the oil. Pour the dressing over the feta and onions and toss well.
Add the drained artichokes to the feta and toss (may be prepared ahead to this point. Will kept refrigerated several days).
When ready to serve, add the tomato cubes and toss everything together. SERVES: 8 to 12