Add the beef, carrots, onion, garlic, and ginger to the bottom of a 6-quart slow cooker.
In a large bowl, whisk together the diced tomatoes, coconut milk, red curry paste, cumin, garam masala, coriander, red pepper flakes, salt, and pepper until well combined. Pour the sauce over the beef and stir everything together.
Cover and cook on LOW for 7 to 8 hours, or until the beef is fork tender.
During the last hour of cooking, stir in the sliced bell peppers. (If you don't mind softer peppers, you can add them at the beginning instead.)
Stir in the lime juice, then taste and adjust the seasoning if needed.
Sprinkle with fresh cilantro and serve with extra lime wedges on the side.