Preheat the oven to 425ºF.
Cook the orzo according to the directions on the packet until al dente.
Roast the vegetables: Place the sweet potato, Brussels sprouts, and red onion into a large bowl. Toss with a generous drizzle of olive oil and salt to taste. Transfer to a large nonstick rimmed baking sheet. Roast for about 20 minutes, or until the sweet potato is fork tender. Toss after 10 minutes so they cook evenly.
Roast the chickpeas & walnuts: Place the chickpeas and walnuts in two separate medium bowls. Toss with a drizzle of olive oil, and salt to taste. Transfer to a small rimmed baking sheet. Place the chickpeas on one side, and the walnuts on the other. Roast with the vegetables on a lower rack.
Remove the walnuts: Remove the walnuts from the oven after about 5 minutes, or once they are golden and fragrant. Continue cooking the chickpeas until the vegetables are ready.
Make the dressing: Meanwhile, add the olive oil, red wine vinegar, maple syrup, basil, oregano, and crushed red pepper to a small jar with a lid. Grate the garlic into the jar using a microplane or fine grater. Add salt and pepper. Cover and shake until well combined. Set aside.
Assemble: Transfer the orzo, sweet potato, Brussels sprouts, red onion, chickpeas, and walnuts to a large bowl. Add the dressing, parsley, and cranberries. Mix to combine. Season with salt and pepper.
For serving: Serve warm or refrigerate for later use and enjoy as a chilled salad.