Preheat oven to 375 degrees F. In a medium pot, cook the couscous according to package directions.
Meanwhile, slice the tops off the tomatoes and scoop out the pulp. You can save the pulp for another recipe (like tomato bisque!) or discard. Place prepared tomatoes in a rectangular baking dish and set aside.
In a large bowl, combine the feta, garlic, oregano, lemon zest (if you don't have a zester or a microplane, try the smallest holes on your cheese grater), salt, and pepper. Add the couscous when ready and stir until well combined.
Divide the couscous mixture among the 4 tomatoes (you may need to pack it in with the back of a spoon to fit it all).
In a small bowl, toss the bread crumbs with the olive oil and sprinkle the crumbs on top of the stuffed tomatoes. Bake for 18 to 20 minutes or until golden brown on top.