If using wooden skewers, soak them in water for at least 20 minutes to prevent burning on the grill.
In a medium bowl, combine the olive oil, lemon juice, soy sauce, garlic powder, paprika, salt, black pepper, and red pepper flakes (if using).
Add the shrimp to the marinade, tossing to coat thoroughly. Let the shrimp marinate for 15 minutes.
Preheat your grill to medium-high heat. If using charcoal, allow the coals to burn down until they are covered with white ash.
Thread the marinated shrimp onto the skewers, leaving a little space between each shrimp for even cooking.
Place the skewers on the grill and cook for about 2-3 minutes on each side, or until the shrimp turn pink and opaque.
Remove from the grill and garnish with fresh parsley before serving.