1. Sprinkle eggplant slices with salt on both sides. Place in a colander over a bowl, and let stand 1 hour to drain. Discard liquid, and rinse under cold running water. Place eggplant slices on several layers of paper towels; press out water.

2. Transfer eggplant to a nonreactive surface. Generously brush both sides with oil; sprinkle with pepper. Heat 2 tablespoons oil in a large skillet over medium-high heat. Add slices of eggplant (without crowding); cook until golden brown on both sides, about 6 minutes. Drain on paper towels. Repeat process with remaining slices.

3. Place the eggplant, onion, feta, olives, and oregano in a large bowl. Drizzle with the remaining olive oil, and season with salt and pepper, if necessary. Gently toss mixture to combine, and serve warm or at room temperature.