In a small pan, mix tomato sauce, enchilada seasoning and salt and pepper to taste. Warm just a bit to mix and set aside.
In a small skillet brown hamburger and yellow onion, drain.
Add 3-4 Tablespoons of the sauce mixture to the meat.
Cut the pita around the outer edge, NOT CROSSWISE, to make it into two "tortillas". Get a small dish, put some sauce on the bottom and the pita on top of it, and then spoon sauce on top as well and spread around. This will make the pita soften a bit and be rollable.
Starting at the edge, place half the meat on the sauce covered pita, top with 1/3 of the cheese. roll and place in baking pan or dish. Repeat the process with the other one.
Spoon sauce over the top of both pitachiladas, and top with remaining cheese. Bake at 350 degrees for 15 mins. Remove cool for at least 5 mins, Top with your favorite salsa or sour cream and enjoy.