Heat 1/2 the oil in a nonstick pan over medium high heat. Add bell pepper and onion; cook, stirring frequently, until pepper starts to brown, about 5 minutes. Add remaining oil. Stir kale, harissa, and garlic into the hot oil until well combined. Reduce heat to medium; splash in 1 to 2 tablespoons of water if needed.
Gradually stir eggs into the kale mixture. Cook, stirring frequently, until nearly set, about 2 minutes. Mix in bacon, feta, and pepperoncini. Heat through. Transfer to a bowl or plate.
