01 - In a medium bowl, combine the parsley, cilantro, garlic, shallot, red wine vinegar, olive oil, oregano, red pepper flakes, sea salt, black pepper, and lemon juice. Stir thoroughly until all ingredients are evenly incorporated.
02 - Set aside 1/3 cup of the chimichurri for finishing. Pour the remaining sauce over the peeled and deveined shrimp in a large bowl or zip-top bag, tossing to coat evenly. Let marinate at room temperature for 15 minutes.
03 - Preheat a grill or grill pan to medium-high heat, ensuring the grates are clean and lightly oiled to prevent sticking.
04 - Thread the marinated shrimp onto skewers, spacing them evenly. If using wooden skewers, soak them in water for at least 30 minutes prior to prevent burning.
05 - Place the skewers on the hot grill and cook for 2 to 3 minutes per side, turning once, until the shrimp are opaque throughout and lightly charred on the edges.
06 - Transfer the grilled shrimp to a serving platter and drizzle with the reserved chimichurri sauce. Serve immediately while hot.