Coarsely chop the peanuts. Heat 1/2 tbsp. oil in a very small pan, add peanuts and roast while turning. Take out and put aside. For the vinaigrette, halve the limes and squeeze the juice.
Mix lime juice, sugar, salt and pepper well. Fold in 5 tablespoons of oil vigorously.
Wash the cucumber, cut off the ends. Cut the cucumber in half lengthwise. Cut 3 strips (3-4 mm thick) of each half of the cucumber evenly lengthwise, so that 6 longitudinal strips (total cucumber length) are formed.
Finely dice the remaining cucumber. Wash apples thoroughly, quarter them, cut out the core and finely dice the flesh. Wash the rocket, shake dry and cut coarsely.
Drain the mozzarella well and squeeze it lightly between 2 layers of kitchen paper. Mix the rocket, cucumber and apple cubes with the nuts. Pour the vinaigrette over it and let it steep for about 15 minutes, mixing several times.
Form each cucumber strip into a ring, while sticking the ends together with a wooden skewer. Place each ring on a plate. Coarsely grate the mozzarella. Spread the salad evenly into the cucumber rings.
Sprinkle with mozzarella. Garnish with an apple slice as desired.