In a large skillet, begin by heating the oil over medium heat until it is hot. One at a time, add the tortillas, and cook for about 1 minutes on each side, or until they are heated thoroughly. Cut each tortilla in half.
Evenly divide the lettuce on top of the 8 tortillas halves. Then, after cutting each tomato into 8 wedges, arrange them on top of the lettuce. Sprinkle with onions and then top with shredded chicken and cheese.
Spoon 2 tablespoons of salsa over each tortilla half, and serve immediately.