Peel jicama & cut into french fry pieces. In a saucepot of boiling water, sprinkle 1/2 tsp salt; add jicama fries & boil for 10 minutes. Drain well. In a large bowl, combine fries with oil, 1/4 tsp salt, garlic powder, cumin & smoked paprika. Coat well, blending spices. Preheat oven to 400 F. Spread fries onto a lightly oiled baking pan & bake for about 30 minutes, turning halfway through baking time, until fries are crisp.