Green: mix a pinch of spirulina and turmeric through the flour
Red: mix some beet powder through the flour
Turquoise: Instead of using regular water use water that has been boiled for 15 minutes with purple cabbage. Add a pinch of baking soda to this water before using it to make the dough.
If you're using a food processor with a dough hook, add the flour and optionally your food colouring of choice to the machine and turn it on. In a steady stream add very hot water through the feeding tube and form a ball of dough. Pinch the dough to see if its soft, but still firm enough to hold its shape. You can add a tiny amount of water if its to dry, or a small amount of flour if the dough it to wet. Knead the dough a little and put it in a plastic ziplock bag or place it in a bowl covered with a damp, wet towel to prevent the dough from drying out. Leave it here for 15 minutes to half an hour.
To knead the dough by hand add the flour and food colouring of choice to a bowl and add the hot water while mixing the flour with a wooden spoon. Once the flour starts to form lumps and its cool enough to handle by hand you can start kneading it. Form a ball of dough and kneed for another couple of minutes until soft, but still firm enough to hold its shape, adding water or flour if needed. put it in a plastic ziplock bag or place it in a bowl covered with a damp, wet towel to prevent the dough from drying out.
I made two batches of dough. And the turquoise I made the day after using a different filling (which I'll share in the near future, because I didn't write it down.)
After the dough has rested kneed it for 30 seconds and take a take about 1/3 from the dough, place the rest back in the ziplock bag or underneath the damp towel.
Flour your working surface and form little balls from the dough, the size of a marble. Roll them flat into circle shaped disk and fill the dumplings, close them and put them on a plate covered with parchment paper. After filling your first batch of dumplings put the plate or tray in the freezer while working your next batch. Once the dumplings are frozen (or partly frozen) you can add them to a ziplock bag and store them in the freezer for about 3 months (although they'll never last this long).
To cook the dumplings you can steam them for a couple of minutes (frozen about 15 minutes) just line the steamer with parchment paper.
Boil them until they float to the top.
Or you can make pot stickers. Heat up some oil in a pan and once hot add the dumplings, cook for about a minute before adding a glass of water, quickly put the lid of the pan on and leave it to steam for about 7 minutes. They should be crispy on the bottom, but not burned.