Add yuca to a large pot of water with salt. Bring the yuca to a boil on high heat then reduce to low. Cover and simmer for about 30 minutes until the yuca is fork-tender.
Heat oil, add onions and sauté until softened. Add in garlic, black pepper, and salt to taste. Sauté for 30 sec then whisk in the juice until all is combined. Set aside.
Drain yuca, pat dry then put in bowl with a lid. Remove the core from each piece. Well coat the yuca in sauce. Cover and allow to cool for 10-15 min. Serve immediately.