Heat oil in a pan over medium-high heat. Add cumin seeds. When cumin seeds begin crackling, add onion. When onion becomes translucent, add ginger and garlic paste. Continue to stir so mixture does not stick to bottom of pan.
Reduce heat to medium, add tomato purée. Use a spatula to break up chunks. Continue to cook over medium heat, stirring occasionally, until oil separates from the mixture. Mix in coriander, red chili powder, turmeric, and salt. Add bell peppers, stir to evenly coat them with spices. When bell peppers are tender, add tofu cubes. Cook for few more minutes, until tofu is coated with spice mixture.
Serve hot with rice, roti, a tortilla or any flatbread, garnished with garam masala and cilantro.