In a large saucepan combine rice and water. Cook over high heat until mixture boils. Reduce heat to low, cover and cook for 45 to 60 minutes or until rice has absorbed all liquid.
Meanwhile, in a small bowl whisk the orange juice, oil, balsamic vinegar, honey, orange zest and salt. Pour dressing over hot cooked rice and mix well. Cover and chill until cold.
Just before serving stir the spinach leaves, oranges and onion into the rice mixture.
