Heat the butter in a saucepan add the onion and cook for about 5 minutes. Add the tomato puree, garlic powder, cumin, chili powder, tomato paste, cilantro and oregano. Stir and cook for two minutes more.
Add the shredded chicken. Season with salt and pepper, cook for about 3 to 5 minutes.
Heat the tortillas on a nonstick skillet or oven, then wrap them in aluminum foil to keep them warm.
To assemble: spread one tortilla with cream cheese, then top with about 2 tablespoons of the chicken mixture, roll and secure with a toothpick. Process with the remaining tortillas.
Heat the vegetable oil in a large skillet and when oil is hot, place about three to four flautas into the oil, and cook for about 1 minute on each side.
Drain the flautas on paper towels. Remove the toothpicks and serve warm with avocado slices, queso fresco and salsa.