Place the hemp seeds and salt in the bowl of a food processor fitted with the S blade. Grind the hemp seeds for about 30 seconds, or until they've formed a fine meal.
Add the chickpeas, lemon, garlic, tahini, cumin, and pepper to the food processor. Pulse a few times. With the motor of the processor running, add the water through the spout of the processor. Process all ingredients until smooth and creamy (about 1-2 minutes), stopping every now and then to scrape the bowl down. Season to taste with black pepper and serve.