Mix the marinade ingredients in a bowl and set aside.
For the fajitas:
Add shrimp to large freezer bag or resealable container. Pour marinade onto the shrimp and toss to coat.
Cover the shrimp and marinate for at least 30 minutes.
Place the peppers and onions in foil. Drizzle with olive oil. Then fold the foil into a packet and poke holes in the top to vent.
Heat the grill to medium heat. Place peppers and onions onto the grill. Shake foil occasionally.
Remove the shrimp from marinade and skewer. Place shrimp on grill and cook for 5-7 minutes, turning halfway. Shrimp will be cooked when pink and opaque.
Wrap the tortillas in foil and place on the grill. Warm the tortillas for 2 minutes.
Remove the shrimp, vegetables, and tortillas from the grill and serve with sour cream, guacamole, salsa, fresh cilantro, or your favorite fajita toppings.