Well, we just parcook them in water, then fry them in oil. It seems it is the bigger, bitter roots that are pressed to extract the starch.
See: http://en.wikipedia.org/wiki/Cassava#Food_use_processing_and_toxicity
Also, this yuca is pronounced yoo-cuh, not yuk-uh!
An aside: raw taro, it turns out, is also toxic raw.