Combine the marinade ingredients in a large Ziploc bag. Add the shrimp and toss gently to coat. Let sit for 30 minutes.
If using wooden skewers, it's a good idea to soak them in water (or lime water for added flavor) for 30 minutes to reduce burning/splintering.
Thread the shrimp onto your skewers.
Preheat BBQ/grill to high. Reduce heat to medium-high, and grill the shrimp for about 4 minutes/side, or until they're pink and gently firm, taking care not to overcook.
Serve with warm, fresh tortillas, salsa and guacamole. Sprinkle with chopped cilantro and a squeeze of lime.