For those of you without access to Activa, just go without and add an egg white to the shrimp in the food processor and make a fine paste with it. Other than that minor adjustment, the recipe stands as follows. The egg white and/or the Activa are really just a bit of insurance since the shrimp should have enough protein to bind the sausages all by itself. Those of us who do this for a living always like to have that extra insurance policy in our back pockets, just in case.
Roughly chop the shrimp. In a large bowl mix the shrimp with the garlic, salt, paprika and cayenne. Take half of the seasoned shrimp and place in the bowl of a food processor. Pulse to form a rough paste. Fold the processed shrimp mixture into the remaining chopped shrimp and then sprinkle one third of the Activa over the mixture. Fold the Activa into the shrimp and repeat twice more with remaining Activa to evenly distribute all of it into the shrimp.
Place the mix in a piping bag and pipe foot long sausages on sheet of plastic wrap. Roll the plastic wrap tightly around the shrimp and twist the ends securely so that the shrimp resembles a foot long sausage link. Repeat with the remaining shrimp. This base makes roughly six links of chorizo.
Refrigerate the shrimp base overnight, then poach the wrapped sausages in a water bath at 52.5 degrees Celsius for forty minutes. Cool at room temperature for 20 minutes then chill the chorizo in an ice bath. When the shrimp chorizo is commpletely cold, refrigerate it until you are ready to use it.
Slice pieces of the chorizo and serve with grilled toast and olive oil.