Bring salted water to the boil in a pan.
Place the chicken in the water and cook over a low heat for approx. 10 minutes.
Remove from the water and slice or tear the meat into pieces.
Divide the chicken on the tortillas and season with salt and ground black pepper.
Roll up the tortillas and fix with wooden cocktail sticks.
Heat the oil in a high-sided pan and deep-fry the tortillas for 4-5 minutes until golden brown and crisp.
Remove the flautas from the oil and drain on kitchen paper.
Arrange them on a large plate and spread the sour cream over them.
Sprinkle over the lettuce, onion and feta over them.
Serve with salsa if wished.