Preheat oven to 400°F. Line 2 baking sheets with parchment paper. Set aside.
Cook the rice according to package directions.
While the rice is cooking, toss the cauliflower and broccoli with 1 teaspoon oil, sprinkle with a pinch of salt and pepper and spread out into one even layer on one prepared baking sheet. Toss the chickpeas and carrots with the remaining 1 teaspoon of oil, sprinkle with salt and pepper, and spread out into one even layer on the other prepared baking sheet.
Roast for 20 to 30 minutes, turning the pans and giving them a shake every ten minutes. (Every oven is different, so keep an eye on everything to make sure you don't burn them.)
While the vegetables are roasting, combine all the dressing ingredients in a small bowl or cup and whisk until smooth. Add more water, as needed, to thin out. Set aside.
To serve, place some rice in a bowl, top with greens, if using, then some roasted vegetables and chickpeas. Sprinkle with sesame seeds and drizzle a few tablespoons of sauce over everything. Squeeze of bit of fresh lemon juice over everything, if desired. Repeat with as many servings as needed.