Set out a medium, oven-safe casserole dish and preheat over to 425F. I used a round casserole dish that was 10" diameter (across) and 1.5" high for a perfect fit.
Put a large pot of salted water on to boil for the orzo. Heat a pan over medium-low heat with the olive oil. Dice onion and saute until almost translucent, about 4-5 minutes. Finely dice garlic and add to the pan. Cook until the raw garlic smell is gone, about 3-4 minutes.
While cooking onion and garlic, drain and dice olives and dice your bell pepper. Add olives, capers, bell pepper, oregano, smoked paprika, tomato paste, can diced tomato, and large pinch of saffron. Crush the saffron between your fingers further while adding to the pan.
Wait to add orzo to your boiling water until now when there are only a couple prep steps left to do while it par-cooks. Make sure your cooking water is well salted, and add your orzo to cook for half the time quoted on the package.
While the orzo is cooking, chop your parsley and add the the pan of vegetables along with the 1 teaspoon of salt and black pepper. Taste and add more salt if you prefer. Open your can of tuna, drain, and mix in while leaving some of the tuna in small bite-sized pieces.
Drain the orzo and add to the bottom of the casserole dish. Layer the vegetable and tuna mixture over top, smooth and pack down. You want the juices of the vegetables to cover and finish cooking the orzo! Sprinkle the parmesan in an even layer over the top. Place in oven for 12-15 minutes, or until brown and delicious. Serve with your favorite salad on the side.