Wash the chicken fillets, dab dry and rub with salt and pepper. Pluck sage leaves from the stalk. Wash lemon, rub dry, grate peel. Squeeze lemon and mix with the peel.
Heat sunflower oil in a pan and fry the meat on both sides for about 5 minutes. About 2 minutes before the end of the frying time, drizzle the zironene juice over the chicken fillet. Braise the sage leaves briefly in the frying pan.
Clean the salad. Cut romaine lettuce into strips, pluck frisée into bite-sized pieces. Clean and halve the tomatoes. For the vinaigrette, mix vinegar, salt, pepper and sugar, and add olive oil.
Arrange lettuce, tomatoes and sliced chicken breast in a salad bowl, drizzle vinaigrette over it. Garnish with lemon wheels if desired.