Bring a large pot of salted water to a boil. Add the yucca and boil until tender, about 30 minutes. Drain and place the yucca on a serving platter.
Heat the oil in a small skillet over high heat, add the onions and garlic and let cook about 1 minute, making sure the garlic and the onions don't start to brown; season with salt and pepper. Pour the onions and garlic directly over the yucca. Pour the lime juice on top and sprinkle with oregano.