1. Heat the grill to hot and grill the peppers, turning occasionally until the peppers are roasted. Remove and place in a plastic bag, making sure to tie them securely. Let cool.
2. Meanwhile, seed the tomatoes and cut them roughly into cubes. Remove the peppers from the bag and remove the skins and discard the stems and seeds.
3. Also dice them and roughly mix the tomatoes and chopped garlic. Transfer to a large skillet and heat over medium-low heat until the water has evaporated.
4. Still over low heat, season with the chilli powder, cumin, salt and pepper. Stir in the chopped cilantro and olive oil, then transfer to a bowl. Cover and refrigerate until cooled, can be eaten warm (serve hot or cold to taste)
5. When ready to serve, pour into bowls and garnish with pinches of ground cumin and a few cilantro leaves.