Prep the tomatoes: Wash and dry the tomatoes. Cut them into even pieces. If using cherry tomatoes, halve or quarter them.
Place in a large mixing bowl.
Salt and rest: Sprinkle the tomatoes with a pinch of kosher salt and let them sit for 5–10 minutes. This draws out juices and concentrates flavor.
Slice the onion: If using red onion, slice it very thin. If you prefer a milder bite, soak the slices in cold water for 5 minutes, then drain and pat dry.
Make the dressing: In a small bowl, whisk together olive oil, vinegar or lemon juice, garlic, dried oregano, a pinch of salt, and black pepper.
If your tomatoes are very tangy, add a tiny pinch of sugar or a drizzle of honey.
Add the feta and onion: Add the feta and red onion to the tomatoes. If using a block of feta, cut into small cubes for creamy, satisfying bites.
Toss gently: Pour the dressing over the salad and toss gently to coat without breaking up the feta too much.
Add the basil last: Tear the basil leaves by hand and fold them in lightly. Tearing helps release aroma without bruising the leaves.
Taste and adjust: Add more salt, pepper, or acid to taste.
If the salad seems flat, a splash more vinegar or lemon can brighten it.
Serve: Transfer to a shallow bowl or platter. For extra flavor, finish with a drizzle of olive oil and a few cracks of black pepper.