Bring water and rice to a boil in a saucepan. Reduce heat to medium-low, cover, and simmer until rice is tender and liquid has been absorbed, 20 to 25 minutes.
Heat oil in a large skillet over medium heat. Add green onions and garlic; cook and stir until softened, about 5 minutes. Stir in spinach and dill until wilted, 3 to 5 minutes. Stir in cooked rice. Transfer to a large serving dish.
Heat a small skillet over medium heat. Add pine nuts; cook and stir until toasted, 3 to 5 minutes.
Top rice with toasted pine nuts, feta cheese, mint, lemon zest, lemon juice, and sumac.
