In a medium saucepan, bring 2 cups salted water to a boil. Stir in the rice, lower the heat, cover and simmer until the water is absorbed, 15 to 20 minutes. Uncover and let stand for 5 minutes before fluffing with a fork.
Meanwhile, slice off the ends of each orange, then stand the oranges on a cutting board. Using a sharp knife and working from top to bottom, cut off the peel and pith in strips. Working over a bowl, hold an orange and make a cut on either side of each segment to release from the membrane; let the segments fall into the bowl. Squeeze the remaining juice from the orange into the bowl. Repeat with the remaining oranges.
In a large nonstick skillet, heat the olive oil over medium-high heat. Add the garlic and cook until fragrant, about 2 minutes. Stir in the spinach and season with salt and pepper; cook until heated through, about 4 minutes. Fold into the cooked rice; wipe out the skillet.
Add the flour to a plate. In the skillet, heat the vegetable oil over medium-high heat. Season the fish with salt, pepper and the cumin; coat with the flour, shaking to remove any excess. Cook until golden-brown and crisp, 3 to 4 minutes on each side. Drain on paper towels. 5. Add the orange segments, juice and olives to the skillet, stirring to scrape up any browned bits; pour over the fish. Serve with the spinach rice.