Rub the pork leg with the onion, salt, soy sauce and paprika, and let it stand in the refrigerator for at least 2 hours (ideally overnight).
Roast in a 170°C oven until nicely golden brown (about 1.5-2 hours, depending on its size).
Dice the gherkins, remove the seeds, and steam them in a little water in a pot until crisp-tender.
Heat the oil in a pan, add the cassava flour and the steamed cucumbers, and fry, stirring constantly, until the flour separates dry and crumbly - this is the farofa.
Spread the farofa on a large platter and place the roast leg in the middle.
Decorate the edge of the platter with iceberg lettuce, chopped cabbage, tomato and bell pepper.