Grate the zucchini, finely chop the pepper, green onion and herbs, chop the pistachios with a knife.
Dry the cumin in a dry frying pan.
Lightly beat the egg. Combine ground beef, egg, zucchini, peppers, herbs, and most of the pistachios in a large bowl (reserve some for garnish). Season with salt and cumin seeds.
With your hands soaked in cold water, shape the minced meat into balls the size of a chicken egg. Spread on a tray and refrigerate for at least 30 minutes. Thread 2 balls onto skewers.
Light the coals, set the grate and heat properly. Oil the grate, arrange the skewers and cook, turning often, 12-15 minutes, until cooked through. Sprinkle with pistachios.