In a large bowl, toss the watercress, romaine, and arugula with 2/3 of the dressing. Put the dressed greens onto a large serving dish. Place the tomatoes on top, forming a row down the middle. In strips/rows on either side of the tomatoes place the avocado, chickpeas, diced tofu, and grilled mushrooms on top of the greens. Sprinkle with the chives, drizzle with the remaining dressing and serve.