Slice the cucumber into long ribbons using a grater or fine peeler. Julienne the fennel. Grate 1 tsp of lemon zest and juice the lemon. Marinate the cucumber and fennel in the lemon juice mix for 10 min.
Score the grapes with a knife. Put the grapes and tomatoes into separate dishes and cover with boiling water. Remove the tomatoes after 1 min. and rinse in cold, running water. Peel off the skin and chop them up. Drain the grapes after 2-3 min. Peel off the skin and cut them in half.
Mix the cucumber and fennel with the tomatoes, grapes and oil. Season with salt/freshly ground black pepper. Sprinkle with dill.