Make Chimichurri Sauce: In a bowl, combine the chopped parsley, chopped oregano, minced garlic, red wine vinegar, and red pepper flakes. Slowly drizzle in the olive oil while whisking continuously to emulsify the sauce. Season with salt and pepper to taste. Set aside to allow the flavors to meld.
Grill the Chorizo Sausages: Place the chorizo sausages on the preheated grill or in a 400F (204C) oven. Cook the sausages to an internal temperature of 160F (71C), turning occasionally, until cooked through and nicely charred.
Warm the rolls.
Assemble the Choripan: Place a grilled chorizo sausage in each toasted roll.
Add Chimichurri Sauce: Drizzle a generous amount of chimichurri sauce over the grilled chorizo sausages.
Mix the ingredients for the lemonade.
Serve the Choripan alongside chips with a glass of homemade lemonade.