Bring yuca with water to cover and 2 teaspoons salt to a boil in a large Dutch oven over medium-high heat. Cover, reduce heat to medium-low, and simmer 25 minutes or until tender. Drain well. Transfer yuca to a large bowl or serving platter, and keep warm.
Stir together remaining 1 teaspoon salt, garlic, and next 3 ingredients in saucepan over medium heat; cook, stirring occasionally, 8 to 10 minutes or until onion is translucent. Spoon garlic mixture evenly over yuca; top with onion rings, if desired, and serve immediately.
*1 (24-ounce) package frozen yuca, thawed, may be substituted for fresh.