Bring a large pan of water to the boil, add the basmati rice and cook for 12 minutes. Drain and cool by rinsing under cold running water. Set aside.
Meanwhile, tip the vegetable antipasti into a large salad bowl and toss together with the drained pulses.
For the dressing, whisk together the lemon juice, mustard and olive oil. Season to taste with salt and pepper and sweeten with a little honey, if you like.
Add the cooked, cooled rice to the antipasti and pulse mixture. Pour over the dressing and toss the salad together well. Fold through the watercress leaves just before serving.