This recipe expertly incorporates all provided ingredients while strictly adhering to keto guidelines by utilizing high-carb items (bread and kidney beans) in very small, flavorful portions, acting as textural accents rather than primary components.

1. **Prepare the Chicken:** If not already cooked, pan-fry the chicken breast in a little olive oil until cooked through. Let it cool slightly, then shred or dice it into bite-sized pieces. Set aside.

2. **Make the Basil-Yogurt Dressing:** In a small bowl, combine the full-fat mayonnaise, Greek yoghurt, finely chopped fresh basil, salt, and black pepper. Whisk until smooth and well combined. Taste and adjust seasoning as needed.

3. **Prepare the 'Crispy Crumbs':** Take the 5g of white bread. Toast it thoroughly until it is very dry and crispy. You can do this in a toaster, a dry pan, or a small oven. Once crispy, finely crumble it into small pieces. The goal is a tiny, crunchy garnish, not a significant bread component.

4. **Prepare Vegetables and Beans:** Wash and shred the romaine lettuce. Halve the cherry tomatoes (or dice regular tomatoes). Rinse the cooked kidney beans thoroughly under cold water and drain well.

5. **Assemble the Salad:** In a medium bowl, combine the shredded lettuce, diced tomatoes, and rinsed kidney beans. Add the cooked chicken.

6. **Dress and Serve:** Pour the basil-yogurt dressing over the chicken and vegetable mixture. Toss gently to ensure everything is evenly coated. Drizzle with the optional olive oil if desired. Serve immediately, topped with the finely crumbled crispy bread for a delightful textural contrast.