Press water out of tofu if necessary. Cut tofu into cubes. Mix soy sauce, oil, and garlic powder in a medium sized mixing bowl. Gently toss tofu cubes until coated. Sprinkle cornstarch or arrowroot powder and gently toss again until evenly mixed. Try to keep tofu cubes intact during this mixing process. Spread cubes out on an ungreased, nonstick cookie sheet. Make sure none are touching and bake at 400 degrees until browned and crisp. Flip halfway through if desired.