Prick the eggplants all over with a fork. Place them on a lined baking sheet and roast in the oven 45-55 minutes until soft. Remove from oven and let cool. Scoop the flesh out and place it in cheesecloth or a dish towel and wring out any excess water. Place the eggplant in a bowl and chop it up.
Stir in the hummus, garlic, cumin, coriander, salt, cayenne, cilantro, and pine nuts. Add the breadcrumbs and stir until combined. Add more breadcrumbs as needed until the mixture holds together.
Place the remaining ½ cup breadcrumbs in a shallow dish. Form the eggplant mixture into meatballs (I like using a small cookie scoop for this) and lightly roll them in the breadcrumbs. Place them on a greased baking sheet. Discard any remaining breadcrumbs. Spray or brush the meatballs with olive oil. Bake in the oven 18-22 minutes until firm. For an extra golden crust, place them under the broiler for a few minutes at the end.
To make the sauce, stir the hummus, yogurt, lemon juice and herbs together in a bowl. Top the sauce with some of the oil and pine nuts from the hummus container. Serve the meatballs with the sauce.