Mix sumac and onions and place in a strainer. Let it drain 20 minutes.
Place all ingredients for kafta into food processor. Add drained onions. Pulse until meat is smooth. Heat oven to 400°.
Using a cookie dough scoop, place kafta on lined baking sheet. Bake 5 minutes, or until fully cooked.
In separate bowl, combine first three ingredients for Tahini Dip. Add water slowly and mix until desired texture is reached.