In Tampico, 'salpicón' is the name for the shredded seafood filling itself, which can be crab, shrimp, fish or tuna.
Fried turnovers stuffed with a seasoned seafood salpicón (crab, shrimp, fish or mixed), sold hot at market stalls such as Mercado La Puntilla, especially during Lent.
Why it's made this way: Seafood salpicón, especially crab salpicón, is a hallmark of Tampico cooking, and the Tampico press describes salpicón empanadas as a local tradition tied to Lent.