Place the couscous in a small bowl and cover with boiling water and lemon juice, keeping the ratio of coucous-to-liquid the same. Cover the bowl with a board or plate. Set aside for 10 minutes.
Finely chop the parsley and mint leaves and place into a large bowl. Using a fork, fluff up the couscous then add to the parsley and mint along with the tomatoes and spring onions.
Season with salt, pepper and a glug of olive oil then mix together until combined. Serve immediately with a lemon wedge or two.