Rinse and pat dry the skirt steak. Place it in a gallon Ziplock baggy. Drizzle 1 tablespoon grapeseed oil and sprinkle 1 tablespoon fajita seasoning. Mix well, squirt the juice of half of a lime over the steak. Seal and place in the refrigerator to marinate for 4-8 hours.
Repeat this process with the shrimp; 1 tablespoon grapeseed oil + 1 tablespoon fajita seasoning. Seal and place in the refrigerator. Slice the bell peppers and onions. Place in a Ziplock bag, drizzle the remaining Grapeseed oil, fajita seasoning and the half of one lime juiced. Mix well and place in the refrigerator.
Once ready to cook--preheat the grill to high heat. Once the grill has reached 500 degrees, reduce to low heat, and clean grill.
Skewer shrimp and set to the side.
Spray with cooking spray. Place the steak on one side of the grill. Add the vegetables to a grill basket and place on the opposite side of the grill. Place shrimp skewers in the middle. Cook for 8 minutes, then turn vegetables.
Flip the steak and shrimp skewers. Cook for an additional 7 minutes until internal temperature of the steak reads 140 degrees and the shrimp are pink. During the last 5 minutes of cooking; wrap the flour tortillas in aluminum foil. Place on the top rack of the grill in indirect heat so they can warm.
Carefully remove the steak from the grill. Place on a cutting board and let rest for 5 minutes. Remove the shrimp, vegetables, and tortillas from the grill. Drizzle fresh lime juice over the meat and vegetables. Serve and let your guest build their own fajitas!