Drain the water from the pumpkin seeds and discard the soaking water. Place pumpkin seeds, greens, lemon juice, garlic (if using), olive oil, and salt in a powerful blender like a Vitamix (use the plunger to get the greens into the blade) and purée until smooth. (Alternatively, use a food processor, but it will be less creamy than using a Vitamix.)

Store in a covered jar. Keeps several days, refrigerated.