Preheat oven to 425. In medium bowl, toss sweet potatoes with oil, salt and cayenne pepper. Spread evenly on baking sheet and roast for 20-25 minutes, stirring halfway through. While potatoes are roasting, chop chicken sausage and sauté in non-stick skillet for 5 minutes or until cooked through. Add spinach and sauté and additional 2-3 minutes. Remove from heat. Once potatoes are cooked, build tacos. Warm tortillas in oven if desired. Add about 1/4 cup of potatoes to tortilla and top with sausage and spinach mixture. Top with Pico, sliced avocado and cilantro. Serve warm.