Beef Kofta Kebabs with Tzatziki

Name: Beef Kofta Kebabs with Tzatziki
Ingredients: 1 pound ground beef (80/20 blend preferred); 1/2 small onion (grated); 3 cloves garlic (minced); 2 tablespoons fresh parsley (chopped); 1 tablespoon fresh mint (chopped); 1 teaspoon ground cumin; 1 teaspoon ground coriander; 1/2 teaspoon paprika; 1/4 teaspoon cinnamon; 1/2 teaspoon salt (adjust to taste); 1/2 teaspoon black pepper (adjust to taste); 1/4 cup breadcrumbs (optional, for binding); 1 egg (lightly beaten, optional for binding)