It's very important that coriander and onion are very finely chopped. Rinse and finely chop coriander. Then peel and finely chop onion. In a bowl combine ground meat, finely chopped coriander, onion, ground cumin, oil and salt. Using your hands mix well, until you have a smooth mixture. Cover and put in the fridge.
Roast the sesame seeds in a pan over medium heat, until lightly brown. Be careful not to burn the seeds. It's important to roast a small quantity of sesame at a time.
Pour the roasted sesame seeds on a plate and let cool. Repeat the process until you've roasted all the seeds. Put sesame seeds in a blender or food processor and blend. If you're using a mortar, put ¼ of the sesame seeds in a mortar and grind them with the pestle. Continue grinding until the seeds are ground down to a fine powder. Put ground sesame on the plate and grind the remaining seeds.
In a bowl combine plain flour and water and mix well, until you have a smooth dough. Transfer the dough to a lightly floured working surface and knead for 3 minutes. Cover with a kitchen towel or bowl and let rest for 10 minutes. In the meantime make the sesame-tomato-dip
Heat 2 tablespoons sunflower oil in a small pot or saucepan over medium heat until it begins to shimmer. Then fry finely chopped half small onion until golden brown. Reduce the heat to low (the lowest setting on your stove). Add freshly grounded sesame seeds and mix well. Stir in ketchup and sugar. Let cook for 3 minutes, while stirring constantly. Remove from heat and set aside for later.
Once your dough has rested for 10 minutes, divide the dough into two parts. Cover one part with kitchen towel or cling film, so that it won't dry out. Lightly flour the working surface and divide the dough into small dough balls, each weighing around 15 g (½ oz). Then you roll out each dough ball separately. Put the dumpling wrappers on a lightly dusted board.
Hold the dumpling wrapper with your left hand. Take the fork with your right hand, take about one and half forks (about 2 teaspoons) of the filling and place it in the center of the dumpling wrapper. Dip your right hand pointing finger in water and dab around the edge of the wrapper. Put your left thump on top of the filling and start folding with your right hand around your thumb. Always grab a bit of the dumpling wrapper, fold it and then pinch it together. Continue folding and pinching until the wrapper edge meets where you've started. (See the video). Put the folded dumplings on a flat plate.
In a steamer pot bring water to a boil. In the meantime grease the steamer pan with sunflower oil and arrange the momos in it. Make sure to leave enough space between the momos since they will expand. Steam the dumplings for 10 minutes. We've used a 2 tier steamer, thus why after 10 minutes we've rotated the steamers and steamed for 5 more minutes.
If you don't have a steamer, you can also use a pot. Fill a medium - pot with one-third water and cover it with aluminum foil. Using a toothpick poke tiny holes in the foil. Don't overdo it. Bring water to a boil over medium-high heat. Reduce the heat to medium - low. Grease the aluminum foil with sunflower oil and arrange the dumplings on top, cover and let cook for about 15 minutes. Repeat the process until you've used up all the dumplings. Serve immediately with the sesame-tomato-dip.
The dumplings taste over the top when served immediately after cooking!!