Place the eggplant slices in a strainer and toss with 2 teaspoons salt. Let drain for 1 hour.

Rinse the eggplant under cool water and thoroughly pat dry with paper towels.

Preheat the oven to 400 degrees F. Line a baking sheet with parchment paper.

Heat 2 tablespoons of olive oil in a large skillet over medium heat. Working in batches, add the eggplant slices in a single layer. Sauté for 5 minutes on each side until soft and golden, adding about 1-2 tablespoons of olive oil per batch.

Arrange the eggplant slices on the baking sheet in a single layer. Top with walnuts and feta cheese. Sprinkle with black pepper and oregano.

Bake until golden, about 10-12 minutes. Serve warm or at room temperature.