In a bowl, toss the chicken with olive oil and cajun seasoning. Season with salt and pepper. Set your grill, grill pan, or skillet to medium-high heat. Grill the chicken until lightly charred and cooked through, turning halfway through cooking, about 10 to 12 minutes. To make the dressing. Combine all ingredients in a glass jar and whisk. Taste and adjust the salt and pepper.Bring a large pot of salted water to a boil. Boil the orzo until al dente, according to package directions. Drain. Add the orzo to a bowl and toss with the pesto. Add the lettuce and 1/3 of the thousand island dressing. Mix in the chicken, roasted peppers, sun-dried tomatoes and cheese. Top the pasta with avocado. Drizzle with more dressing. Serve warm or cold.