Wash or peel the cucumber and cut it into even slices. Wash and slice the tomatoes and dates. Roast the sunflower seeds in a dry frying pan until golden brown. Mix the lettuce, tomatoes, dates, blueberries and cucumber with the dressing. Sprinkle with the sunflower seeds and crumble the goat cheese on top.
Mix the balsamic vinegar, lemon juice, mustard and honey and season with salt and pepper. Whisk in the oil. Keep the remaining dressing in the fridge for one week.