Start by dissolving the salt in the warm water.
Place the masa flour in large bowl and add the water. Mix with your hands until you have a soft ball and all the flour is incorporated. Make a ball with the dough, cover with cling wrap and let it rest for 30 minutes.
Meanwhile fry the sliced onions in a little oil with the cumin, paprika and one chipotle (that you have diced finely). Add the beans after 5 minutes and warm through. Feel free to add more chipotles if you can handle it.
Slice the tomatoes, chop up the coriander and shred the lettuce.
Once 30 minutes has passed it’s to to make the tortillas. Usually after this period you need to make some adjustments - Too dry: it will start to crumble, you need to add more water. Too wet : it will be sticky on your hands you need to add a bit more masa.
It should have a texture similar to playdough.
Once you’ve got the texture right roll into a log and slice into 15 equal sized circles. Place under a damp tea towel to stop the dough drying out.
Take one ball and place in the centre of tortilla press (making sure you’ve got baking paper on each side to stop it sticking) and press down. They should be 1 to 2mm thick and a nice round shape.
Alternatively, place one of the balls in between baking paper press down with the palm of your hand to start you off and then roll out with a rolling pin to the correct size.
Cook on a medium/high heat in a dry, large frying pan for one to two minutes on each side. The tortilla should be lightly coloured and have small air pockets. Keep them warm in a low oven covered with a damp tea towel.
Once you’ve cooked all of them fill tortillas and serve immediately.