Dice onion. Finely slice garlic. Fry onion and garlic in part of the olive oil for approx. 5 min. on medium heat. Stir in tomato paste and fry briefly. Add couscous, pour in boiling water, and set aside to soak and cool down.
Quarter tomatoes. Chop arugula roughly, and basil finely. Quarter olives. Crumble feta.
Season couscous with salt, pepper, lemon juice, and remaining olive oil. Add tomatoes, olives, basil and half of the arugula, and combine. Place salad on top of the remaining arugula. Top with crumbled feta.