Preheat oven to 400 degrees F.
Roll thawed, but still cool, puff pastry into a rectangle about 8 by 10 inches. Place on a baking sheet. Scatter crumbled feta evenly over pastry, then scatter on chopped sun-dried tomato and artichoke hearts and the oil that still clings to them.
Scatter oregano leaves on top of vegetables. Distribute pecans evenly over oregano, then season with black pepper to taste.
Place pizza in preheated oven and bake 20 minutes, or until puff pastry dough bakes up crisp and brown and the pecans are toasted. Cut into 8 or 16 appetizer portions and serve at once.