Pre-heat an oven to 300 degrees Fahrenheit.
Dice the tomatoes and onion. You may need to drain the tomatoes some, otherwise the mixture turn out too wet, which will sometimes result in liquid run-off from a completed pita pizza. Combine in a bowl.
Add into bowl the parsley, scallions, salt and pepper.
Crumble the feta into the mix, trying to avoid large chunks. If the feta came in a package that contained excess liquid, drain first.
Dash in some olive oil, and knead the mixture until it is relatively homogeneous.
Put the pita bread into the oven, directly on the rack, and let them bake for five to six minutes.
Remove the pita bread, and spread liberal dollop of the mix onto each.
Return the pitas to the oven, baking for another five to six minutes.
Remove the pita pizzas from the oven to cool, and if necessary attempt to drain any of the excess liquid that may have accumulated.
The mixture does not need to be used all at once, and may be refrigerated for several meals.