Chop 1 red pepper, 1 small red onion and 2 sticks of celery. Place in a bowl and add 1 small can of tuna in spring water, a squeeze of lemon juice and 2 level tbsp of extra-light mayonnaise. Mix together until well combined and season with black pepper. Cut two 15 cm pieces of wholegrain baguette in half horizontally and fill each with lettuce leaves and the crunchy tuna mixture. Follow with 1 kiwi fruit and a 125g pot of Activia Greek Style Juicy Lemon Yogurt for each person.