This colorful salad is hearty enough to serve as a main course.
Preheat oven to 425 degrees. On 2 large, rimmed baking sheets, toss together sweet potatoes, mushrooms, cumin, and oil; season generously with salt and pepper. Roast, rotating sheets halfway through, until vegetables are tender, browned, and dry, about 40 minutes. Reserve 4 cups sweet potatoes and mushrooms (see Cook's Note below).
In a large bowl, combine arugula with the sauteed corn and 6 cups of the roasted sweet potatoes and mushrooms; toss until arugula wilts slightly. (If you don't have leftover sauteed corn, dress the salad with a simple vinaigrette.) Serve immediately, topped with tortilla strips and crumbled goat cheese, if desired.
Reserved sweet potatoes and mushrooms can be used to make Quesadillas with Chicken Sausage and Roasted Vegetables. Cool completely before refrigerating in an airtight container, up to 2 days.