After a bit of research I decided to start with making my own corn based tortillas. I went to the health food shop, the supermarkets etc to look for "masa harina"-fine ground corn flour processed with lime... No such luck. If I dont find any, can I replace with regular corn meal or the fine powdery white corn flour?
Sorry, you can't make tortillas from regular corn meal.
It's not the same thing. Masa harina has been nixtamalized which changes the properties of the corn, making the protein and other nutrients easier to digest.
A friend in Alabama says she has had some luck with grinding canned hominy (similar process) and pressing it in a colander and drying it then grinding it again but it is a time-consuming project and I don't think she is truly pleased with the results.
Some friends who visited Israel a couple of years ago found a Mexican restaurant not too far from Tel Aviv and they sent me the URL to pass on to other folks who had planned a trip over there and who keep kosher and this restaurant is so. You might phone them and ask if they can recommend a source.
Amigos Mexican Grille
(They tried another Mexican restaurant in Jerusalem which was not even remotely authentic with "tortillas" which were sort of like pita.)
You can't make tortillas from Hominy... but I did recently make Hominy Cakes from some Pozole leftovers based on a recipe in the CONACULTA series.. and those were pretty delicious & simple.... grind the hominy, mix in an egg & a tablespoon of masa harina per cup.. add in some leftover proteins and/or cheese... panfry or roast on a cookie sheet. They are very nice with a Guajillo sauce.