Heat oven to 200C/180C fan/gas 6. Place the tortilla pieces on a baking tray, toss with the oil and the seasoning mix, then cook for 10-12 mins until crisp. In a large bowl, toss the iceberg, beans and tomatoes. Toss the avocado in the lime juice and add to the bowl.
Drizzle over your chosen dressing and toss to coat all the ingredients. Top with the croutons and coriander, then serve.