Preheat the oven to 375°.
Tzatziki: Combine all of the ingredients together into a small bowl and mix. Keep cool until serving.
Meatballs: Combine the lamb, egg, bread crumbs, onion, garlic, cumin, salt and pepper together into a large bowl and mix.
Once combined form 16 meatballs and place them on a sheet tray lined with parchment paper and bake them in the oven for 20 to 22 minutes or until browned and cooked through out.
To Assemble: Serve the lamb meat balls on a pita bread slice and add on some tzatziki, diced tomatoes, sliced onions and lettuce.
Optional toppings: sliced cucumbers and Israeli salad.