Heat oil in a heavy-bottomed pot. Add onions and sauté on medium heat until soft and evenly brown, about 5 to 7 minutes. Lower heat and add crushed ginger and garlic. Fry for 30 seconds until fragrant. Add diced chili. Increase heat to medium-high and add ground beef. Crumble with spatula and season with salt and pepper. Fry for roughly 10 minutes, stirring constantly, until the oil begins to separate from the meat. Stir in crushed tomatoes, tomato paste, red chile flakes, oregano, and ¼ tsp salt. Add 1 cup water and cover with tight-fitting lid. Let the sauce cook on low heat for 40 minutes, stirring occasionally to make sure it doesn’t stick. Add a splash of water to deglaze the pot if needed. Remove from heat and check for salt and pepper, adjusting seasoning as needed. Cook spaghetti (or pasta of choice) as per packet instructions. Drain. Serve keema sauce alongside spaghetti or mix it in a large bowl and serve with a side of ketchup.