Using a sharp knife, cut each yuca root crosswise into 212- to 3-inch-long pieces; cut each piece into fourths. Cut the center stems from each yuca piece. Cut each piece into 12-inch-thick strips.
In a large saucepan combine the water and 1 teaspoon of the kosher salt. Bring to boiling. Add yuca strips; reduce heat. Simmer, covered, about 15 minutes or just until yuca strips are tender. Drain; rinse with cold water. Pat dry with paper towels. Set aside until ready to fry.
In a medium saucepan heat oil to 350 degrees F. Drop 10 to 15 yuca strips into hot oil. Fry for 7 to 9 minutes or until fries float and are crisp and light brown on the edges. Transfer to paper towels; drain well. Repeat to fry the remaining yuca strips. Sprinkle with the remaining 1 teaspoon kosher salt. Serve immediately.