For the croquettes
In a bowl, place feta, ricotta, cumin, marjoram, eggs, salt, pepper and mix well with a wooden spatula. Mold the mixture into small balls and set aside.
Prepare the vinaigrette by placing all ingredients in a jar. Cover and shake vigorously.
Dip the cheese balls, one by one, in the flour, then in the eggs and finally in the shredded fillo. Roll the balls in the shredded fillo until they are completely covered. Heat the sunflower oil in a deep frying pan and fry the croquettes for 2-3 minutes on each side until lightly browned.
Scatter the watermelon cubes on a platter and drizzle with the vinaigrette. Then scatter the croquettes on the same platter and sprinkle with sesame seeds and cilantro.
For 1 cup of watermelon juice, you will need about 2½ cups of diced watermelon. To make the juice, cut the flesh of a watermelon into small pieces. Place the watermelon pieces into a strainer, set over a deep bowl and stir the watermelon for 10 minutes, occasionally pressing the watermelon against the strainer with a spoon to help release the juice. Strain the juice before using.