Heat 2 tablespoons olive oil in a large saucepan over medium-high heat. Add orzo; cook, stirring, until golden, 5 to 7 minutes.
Add 4 cups water and lemon zest; season with salt and pepper; bring to a boil. Reduce heat to medium; cover, and simmer until orzo is al dente and liquid is absorbed, 10 to 15 minutes (if orzo is cooked but liquid remains, cook uncovered to evaporate).
Remove from heat. Stir in parsley, remaining 2 tablespoons olive oil and lemon juice.