1. Cook pasta according to packet directions. Drain.
  2. Heat oil in saucepan. Add walnuts, stir constantly over high heat until light brown.
  3. Reduce heat; add onion and garlic cook 3-4 minutes until softened.
  4. Add spinach and tuna liquid, cover and cook until spinach just wilts.
  5. Flake the tuna and gently toss into the spinach mixture with the pasta.
  6. Add lemon rind, juice and salt and pepper to taste.