Heat oil in a skillet over high heat. Saute chicken pieces in hot oil for 6 to 7 minutes. Do not overcook!
Preheat oven to 425 degrees F (220 degrees C).
To Assemble Pizza: Spoon 1/4 of peanut sauce onto each pita. Sprinkle 1/4 of the browned chicken and 1/4 of the scallions on top of each. Top each 'pizza' with 1 slice cheese. Place on a lightly greased cookie sheet and bake in the preheated oven for 10 to 12 minutes, until the cheese is melted and bubbly. Let stand for 1 to 2 minutes outside of oven before you cut with a pizza cutter.