Peel the yucca and boil in 2 gallons of salted water until soft (about 20-30 minutes depending on the quality of the yucca).
Remove from the water and drain well.
You can separate the yucca into pieces, but it is customary to leave them as they are or just cut in half lengthwise. Some people like to remove the centre core (string) after the yucca is cooked.
To prepare the Mojo sauce: Slice onions and Cuban peppers in long medium wide strips.
Dice the "Ajies Gustosos", make sure you have removed and discarded all of the seeds.
Heat half of the oil till very hot, add the garlic, onions and peppers and sauté for 2 minutes stirring constantly.
Then "deglaze" with the vinegar and follow at once with the other half of the oil, lower heat immediately and simmer for 2 more minutes.
Adjust salt and pepper and remove from the heat. (A mojo sauce should have a definite vinegar flavour, but not so strong as to be overpowering).