Combine the meat, pistachios, onions, cumin, black pepper, red pepper and mix well. Refrigerate 2 hours or overnight.
Lightly knead parsley into the mixture. Roll into tablespoon size balls. Brown on a grill pan. Drain on paper and serve with tahina sauce.
For the tahina sauce
Whisk lemon into the tahina, gradually add water until smooth. Season with salt. Add the garlic, black pepper and nigella seeds. Keep at room temperature.