Bring wheat berries to a boil in salted water and simmer for 1 hour.
Alternately, wheat berries can be soaked in cold water overnight, then cooked for 30 to 40 minutes until tender. Drain and rinse to cool.
In a sauté pan over medium heat, add oil and leeks and sauté until tender, about 5 minutes.
Add courgette and red pepper and sauté 5 minutes more.
Remove from heat and stir in peas, oregano and lemon zest. Once vegetables and wheat berries are cooled, combine together.
Stir in lemon juice and season to taste. Chill until ready to serve.