Saute the couscous in a pan till lightly browned. Cook off in boiling salted water. Rinse in cold water when done.
The lemon zest should be finely minced. Whisk the lemon zest, lemon juice, salt, oil and some black pepper. This mixture may seem salty, but is fine when added to the pasta.
Add the feta and mint to the lemon mixture and toss to coat.
Add the pasta. Adjust seasoning. Chill.