In a pot of boiling water, cook the yucca until tender, but not falling apart and losing its shape, about 10 minutes. Remove the yucca from the water, and dunk into an ice bath to stop the cooking process (shocking) and set aside.
Meanwhile, make the mojo. In a blender, place half of the red onion, garlic, parsley, cilantro, and lime juice. Start to puree and slowly drizzle in the olive oil. When well pureed, season with salt and pepper and set aside. Julienne the remaining half of the onion.
Heat 2 inches of oil in a deep cast iron skillet to 375 degrees F. Begin frying the partially cooked yucca until golden brown, about 5 minutes.
When uniform in color, remove the yucca from the oil and place in a bowl. Season with salt and pepper. Pour the mojo over the yucca, and garnish with the other half of the red onion.