Combine the garlic, cilantro, lime zest and juice, salt and pepper in either a mortar and pestle or food processor. Then, pour in the olive oil to make a smooth paste.
Peel and devein the shrimp (if needed) and combine with the garlic cilantro mixture in a container with a lid. Allow to marinate for up to 2 hours.
Preheat the grill over medium-high heat. Place the shrimp on skewers (no need to leave space between them, fit as many of them on as you can). Grill on direct heat about 2 minutes per side until they are opaque and have formed a crust.