Combine beef and onions in large skillet.
Brown, stirring meat to crumble.
Salt to taste, about 1/2 tsp.and stir in the taco seasoning mix and add water.
Cover and simmer 10 minutes.
In a 13 x 9 x 2 baking dish, place 5 quartered tortillas, coated with taco sauce, overlapping in two rows.
In a wire strainer press out most of the water from the spinach.
Stir half of the spinach into the beef mixture.
Spoon half of the beef spinach mixture over the tortillas in the casserole and sprinkle with half the cheese.
Cover with remaining tortillas coated with taco sauce and spread the balance of tacomeat mixture on the tortillas.
Spread evenly the chopped pork or ham over the tortilla meat mixture and spread on the sour cream.
Put remaining spinach over the cream.
Top evenly with remaining cheese.
Refrigerate several hours or overnight.
When ready to cook, take out of refrigerator early enough so that it is almost at room temperature.
Bake at 375 degrees for 50 minutes, covered for the first 30 minutes.
Before serving, garnish with sliced olives and sliced green onions.
Note: If desired, bake in two 8"x8"x2"casseroles.
Fix one, freeze the other one for a later dinner.