Heat the cooking oil in a wok or other shallow pan. Saute the garlic, ginger, onion, cumin seeds and kaffir lime leaf just until fragrant. Add the carrot cubes, beans and diced bell pepper. Saute for about a minute.
Add the mussels to the pan, pour in half a cup of water and season with patis and black pepper. Cover the pan tightly and let the mussels cook in the steam for about four minutes. You want the shells to partially open but the mussels should only be half-cooked at this point.
Turn off the heat and pick out the mussels. Pry open the shells (careful, they are hot) and discard the empty half shells.
Turn on the heat once again. Add the turmeric powder and chili sauce to the vegetables. Stir. Taste. Add more patis and pepper, if needed.
Add the rice to the vegetables. Stir until the coloring is even. Stir in the half-cooked mussels. Cover the pan, set the heat to the lowest setting and let everything finish cooking in the hot steam for five to seven minutes.
Fluff up the rice before serving.