Step 1

Heat ¼ cup oil in a large skillet over medium-high. Add lemon slices and cook until lightly charred around the edges, about 2 minutes per side. Transfer lemon slices to a medium bowl. Set aside skillet with oil.

Step 2

Break feta into large pieces and add to bowl with charred lemons along with oregano and remaining ½ cup oil; season mixture lightly with salt and generously with black pepper. Toss very gently to coat and set aside.

Step 3

Set reserved skillet over medium-high heat and add frying peppers. Cook, shaking pan occasionally, until skins are lightly charred and flesh is tender, 6–8 minutes. Transfer peppers to a cutting board and let cool slightly, then cut in half lengthwise.

Step 4

Toss onion, cucumber, tomatoes, vinegar, and a large pinch of salt in a large bowl. Add frying peppers and lightly toss again to combine. Transfer salad to a platter and scatter marinated feta with lemon slices and oil over.