Dice the skinned seedless plum tomatoes. Dice the avocado, dress with lemon juice. Dice the skinned smoked chicken, arrange 4 x 4in diameter by 4 inch height of plastic tubing on a tray. Firstly put two teaspoons of tomato in the bottom of each tube. Then put two teaspoons of smoked chicken in each tube. Place two teaspoons of chopped avocado on top of the chicken. Repeat the first three steps then place two teaspoons of creme fraiche and wasabi on top to finish. Place tower in centre of large plate and arrange the mizuna/rocket around this and drizzle with olive oil and sweet soy sauce. Remove plastic ring from tower and serve.