Beat the eggs in a bowl until airy; set aside. To a non-stick skillet add the olive oil and red onion. Allow it to cook over medium-low heat for 1-2 minutes before adding the collard greens. Once the greens have warmed through, set them aside.
Pour the beaten eggs into the skillet and let it cook on one side until it forms enough to flip. Once the omelet is flipped spread the collards, feta, and red peppers down the center. Fold both sides of the eggs overlapping the center and remove it from the pan to serve.