Heat oven to 425. Line 2 baking sheets with parchment paper. Arrange chopped carrots, zucchini into a single layer on the first sheet and the potatoes into a single layer on the second. Drizzle all the veggies with olive oil and season with salt and pepper. Toss to coat. Roast the carrots and zucchini for 20-25 minutes or until tender. Roast the potatoes for 30-35 minutes or until tender.
DRESSING:
In a small bowl, combine lemon juice, tahini, garlic, salt and olive oil. Mix to incorporate. If too thick, add a little warm water. Set aside.
ASSEMBLE SALAD:
In each of 4 salad bowls, place 1 cup salad greens; 1/4 of the potatoes, zucchini and carrots; 1/2 an avocado; 2 TBS toasted walnuts and sprinkle with hemp hearts (optional). Top each salad with 1/4 of the lemon-tahini dressing just prior to serving.