Roasted Sweet Potato Salad with Black Beans and Chile-Lime Vinaigrette

2 medium sweet potatoes, peeled and cut into 1-inch chunks 1 large onion, preferably red, chopped 1/2 cup extra virgin olive oil Salt and freshly ground black pepper 1 to 2 tablespoons minced fresh hot chile (jalapeño, serrano) 1 clove Read on!