In a medium bowl, combine ground beef, olive oil, chopped onion, ginger garlic paste, cayenne, baking soda, bread crumbs, and salt. Shape into long meatballs, about 1 inch wide and 3-4 inches long. In a deep pan, add vegetable oil until 1 inch deep over medium heat. Once thoroughly heated, add the kebobs in batches, turning to brown all sides. Remove to towel lined plate.
In a blender, add tomatoes, garlic, black pepper, cayenne, ground coriander, and 3/4 teaspoon of the ground cumin. Blend until smooth.
In a large deep pan, drizzle olive oil over medium high heat. Once heated, add the remaining 1/2 teaspoon cumin, coriander seeds, peppercorns, and salt. Once spices are fragrant, stir in the tomato mixture. If too thick, add a little water. Gently stir in browned kebobs and decrease temperature to medium low. Cover and cook for 10-15 minutes.
Serve immediately with flatbread and garnish with ginger slices and cilantro.