In a nonstick skillet, heat 1 1/2 teaspoons of the oil. Add the red onion and cook over moderate heat until softened, about 5 minutes. Add the turkey bacon and cook over moderately high heat, stirring, until browned, about 3 minutes. Add the spinach and tomatoes and cook until the spinach is wilted, about 2 minutes. Transfer to a bowl and season with salt. Wipe out the skillet.

In a bowl, whisk the whole eggs and egg whites and season with salt. Heat the remaining 1 1/2 teaspoons of oil in the skillet. Add the eggs and cook over moderate heat, stirring gently, until set, 3 minutes. Remove from the heat and stir in the bacon mixture, feta and chives.

Spoon the egg mixture down the center of each tortilla and top with the lettuce. Fold in the sides of the tortillas, then fold the bottom of the tortillas over the filling and continue to roll until the filling is enclosed. Cut the burritos in half and serve.