Heat olive oil in a nonstick pan over medium heat.
Add red bell pepper and sauté for 1 minute.
Add spinach and cook until just wilted, about 30 seconds.
Pour beaten eggs over the vegetables, tilting the pan to spread evenly.
Season with salt, pepper, and oregano.
When eggs begin to set but are still slightly wet on top, sprinkle with feta cheese.
Using a thin spatula, fold the egg in half, then in half again to create a square.
Cook for another 30 seconds, then flip and cook for 30 seconds more.
Place the folded egg on the bottom half of the ciabatta roll and top with the other half.