Soak wooden skewers for 20 minutes if using. Metal skewers do not need soaking.
In a large mixing bowl, combine olive oil, lemon juice, lemon zest, minced garlic, smoked paprika, cumin, salt, black pepper, and red pepper flakes (if using). Whisk until fragrant and fully blended.
Pat shrimp dry with paper towels, then add to the marinade bowl. Toss until evenly coated.
Let shrimp marinate at room temperature for 10–20 minutes (avoid longer, as lemon juice can overcook tender shrimp).
Preheat grill or grill pan to medium-high heat. Lightly oil the grates with cooking spray or a small amount of oil.
Thread shrimp evenly onto skewers, leaving small gaps between each piece for even cooking.
Grill shrimp for 2–3 minutes per side, until shells (if left on) turn pink and meat is pink/opaques. Avoid overcooking to prevent rubbery texture.
Remove skewers from grill, spritz with additional lemon juice, and sprinkle with chopped parsley. Serve immediately with lemon wedges for squeezing.