In a large bowl, combine mayonnaise, yogurt, pesto sauce, lemon juice, salt and black pepper.
Put chicken, celery and walnuts in a bowl with dressing.
On each of 10 slices of base bread, put 1/2 cup of chicken salad, 2 tablespoon on top. tablespoons of fried pepper and 1 lettuce, cover with the remaining 10 halves, lids.