Peel and very finely chop onion and soak in water while preparing the rest. (Use a colander and submerge in a bowl with water and add onion, in order to easily fish it all out afterwards. This is to remove the bitterness of the onion).
Wash and destalk coriander and chop leaves.
Wash and very finely chop tomato.
Wash, deseed and very finely chop jalapeño(s).
Heat a pan over medium heat (NO OIL).
Grate cheese and divide into 8 piles.
Once pan is hot, add a flour tortilla, sprinkle about 25g grated cheese (one pile) evenly on top, add slices of ham evenly on top, sprinkle another pile of cheese evenly on top and place another tortilla on top.
Bake for about 2-3 minutes until desired color and flip.
Repeat another 3 times.
Now in a bowl mix together chopped onion, chopped coriander, chopped tomato and chopped jalapeño(s), add a little salt and juice of 1 lime. Salsa is ready. Enjoy with Sincronizadas!