Unwrap the asparagus and snap it by hand – it will naturally break where the woody part begins. The tip (the crown) is the tastiest part, so handle it carefully. The woody ends can be used for stock or discarded.
Peel the remaining asparagus gently with a vegetable peeler, taking care not to damage the tips. Only peel the stalks thinly, mainly removing the thicker outer layers.
Soak the asparagus in water for a short time. This is important because sand can get trapped in the tips. Soaking helps remove any dirt.
Rinse thoroughly under running water.
Cut the cleaned asparagus into smaller pieces, then place them in boiling salted water and cook until tender-crisp. This takes about 5-7 minutes. Remove with a slotted spoon and immediately place into ice water to stop the cooking process.
Once cooled, you can store the asparagus in the fridge for a few days or use it immediately in this salad.
Measure the water and bring it to a boil in a small saucepan. Add a pinch of salt. Once boiling, remove from the heat and stir in the couscous. Cover and let it sit for 5 minutes.
When the couscous is ready, mix in the tuna, halved tomatoes, a pinch of salt, salad greens, feta cheese, and green asparagus. Drizzle with lemon juice and serve immediately.