In a small bowl, combine all of the ingredients. Season with salt and pepper. Set aside.
In a pot, bring the water and salt to a boil. Remove from the heat. Add the bulgur. Cover and let sit for 15 minutes. Fluff the grains with a fork and transfer to a bowl. Add the parsley and green onions. Transfer half of the bulgur mixture to another bowl.
Add the cherry tomatoes, oil, lemon juice, mint and garlic to one of the bowls of bulgur. Season with salt and pepper. Mix well and set aside.
To the second bowl of bulgur, add the beef, garlic, lemon zest, salt and spices. Mix well. Divide the mixture into 8 equal portions. With lightly oiled hands, form one portion of meat at a time into a 5-inch (12.5 cm) long sausage. Thread each sausage onto a skewer or chopstick, if desired. Set aside on a large plate. Lightly oil the keftas.
Preheat the grill, setting the burners to high. Oil the grate.
Grill the keftas for 8 to 10 minutes, turning them over frequently, or until the meat is cooked through. Serve the keftas with the tabbouleh, sumac sauce and pita bread, if desired.