In a large Dutch oven or heavy pot, heat one tablespoon of the olive oil over medium-high heat. Add the lamb, ½ teaspoon of salt, and black pepper. Cook until the lamb is nicely browned, breaking it apart with a spoon. Use a slotted spoon to transfer the lamb to a plate, and drain the pot of all but 2 tablespoons of the fat.

Add the onion and garlic to the pot and cook over medium-high heat, stirring occasionally, for about 5 minutes, until golden and tender. Add the cinnamon, oregano, cumin, coriander, and crushed red pepper. Continue to cook, stirring, 1-2 minutes, until fragrant. Add the mashed tomatoes, and cook, stirring occasionally, for 10 minutes. Add the diced tomatoes and 2 cups of water. Bring to a boil, then turn the heat to low and simmer, stirring once or twice, for 15 minutes. Transfer the cooked ground lamb back into the pot and stir to combine. Cover and cook, stirring occasionally, for 20 minutes. Fold in the spinach and season with salt and pepper to taste.

Cook the orzo in a large pot of boiling water according to package directions. Drain well, reserving some of the pasta cooking liquid. Toss with the remaining 2 tablespoons of olive oil, the chopped parsley, and lemon juice. Add a bit of pasta water a tablespoon at a time if it seems dry. Place the orzo on a generously sized serving platter. Ladle the lamb and sauce over the orzo, then top with the chopped olives and crumbled feta. Serve warm.