Combine salsa ingredients in a bowl, then refrigerate until needed. Place shrimp in a food processor and pulse until almost a mince. (Shrimp could also be chopped to this state by hand). Place in a bowl with remaining ingredients, except cornmeal and oil, and mix well to combine. Place the cornmeal in a wide, shallow dish. Dampen hands lightly with cold water and shape 1/4 cup amounts of shrimp mixture into balls. Set the balls - there should be 8 - on the cornmeal. Sprinkle the top and sides with cornmeal and form the balls into cakes about 3 inches wide and a inch thick. Heat the oil in a large non-stick skillet over medium heat. Cook the shrimp cakes for 3-4 minutes per side. Place two cakes on each of 4 plates. Place a spoon of salsa alongside.