In a large cast iron skillet, heat oil over medium-high heat. Add onion, and cook until onion is soft and starting to brown, about 15 minutes, stirring occasionally. If onion starts cooking too quickly, add a little water to the pan to slow the cooking. Add orzo and cook until orzo starts to toast, about 2 minutes. Stir in broth, smoked paprika, saffron, salt, and pepper. Cover skillet, reduce heat to low and simmer until liquid is absorbed, 8 to 10 minutes.