Combine the yogurt, tomato paste, garlic, ginger, lime juice, garam masala, paprika, salt, turmeric, red chili, and black salt in a large bowl. Whisk until smooth and adjust the seasoning—the marinade should be punchy and salty.

Fold the tofu, onion, and bell pepper into the yogurt mixture until every piece is thickly coated. Cover and refrigerate for at least 12 hours or up to a full day to let the flavors penetrate the tofu.

Preheat the oven to 450°F. Thread the marinated tofu and vegetables onto skewers, alternating pieces for variety, while reserving any leftover marinade for basting. If using bamboo skewers, soak them in water for an hour beforehand to prevent them from burning.

Line a square baking dish with foil and balance the skewers across the rims of the pan. The tofu should be suspended, touching neither the bottom nor the other skewers, to allow for even airflow and browning.

Bake the skewers for 15 minutes, until the edges start to brown. Remove from the oven, brush with the reserved marinade, and rotate the skewers before baking for another 10 minutes. For a traditional charred finish, switch to the broiler for the last minute or two until the edges are dark and slightly singed.

Finish with a sprinkle of chat masala and fresh cilantro. Serve hot while the edges are still crisp, with lemon or lime wedges on the side.