Combine the dressing ingredients in a large bowl. Blend until smooth with an immersion blender. Set aside.
Preheat Blackstone griddle to medium heat. Drizzle vegetable oil then add the bell pepper, onion, and chicken. Season with salt, pepper, and fajita seasoning. Cook for 10-12 minutes until the chicken is fully cooked and the vegetables are tender. Remove from the griddle and place in a large mixing bowl.
Add the dressing, lettuce, tomatoes, and cilantro to the mixing bowl with the chicken. Mix thoroughly.
Lay out the 8 tortillas and evenly divide the salad mixture between them. Roll like burritos and slice in half. Serve immediately.
