Step 1 Mix 1 tablespoon of the lemon juice,1 teaspoon of the olive oil and garlic in a shallow glass or ceramic dish. Add lamb and turn to coat; cover and place in fridge to marinate for at least 15 minutes.
Step 2 Spray a large grill pan or non- stick frying pan with olive oil and set over medium–high heat. Cook lamb for 3 minutes per side (for medium), or until done to your liking. Transfer lamb to a plate, cover loosely with foil and leave to rest for about 3 minutes.
Step 3 Meanwhile, prepare couscous according to packet instructions. Fluff and separate grains with a fork; add mint and set aside.
Step 4 Meanwhile, steam or boil all peas and asparagus for 2 minutes, or until just tender; refresh under cold running water, then drain. Transfer vegies to a large salad bowl with remaining lemon juice and olive oil, extra mint and feta; toss lightly to combine.
Step 5 Cut grilled lamb into thick slices and serve with herb couscous and mint-pea salad.