Pour both cans of enchilada sauce into a 2 quart sauce pan, bring to a boil, immediately reduce heat, stir and simmer for 2 minutes Remove from heat.
Add 1/2 cup of heated sauce to the bottom of the casserole dish and spread evenly. Save remaining sauce.
In a large skillet, over the Med-High setting, heat corn oil. When the oil is hot add 3 corn tortillas at a time, sizzling approx 5 seconds turn with tongs and heat an additional 3 to 5 seconds (or until soft - do not allow them to get crisp). Use paper towels to drain the heated tortillas and layer 6 of them over the sauce in the dish.
Add a third of the minced onions and jalapenos followed by a third of the cubed and shredded cheeses and lightly salt. Pour another 1/2 cup of sauce over cheese. Repeat layers twice, ending with all remaining cheese, onion/jalapeno mix, cheese, sauce and salt.
Bake uncovered at 350 F for 20 mins or until cheese is melted and bubbly -do not allow to brown. Remove from oven and allow to rest 5 minutes.
Cut into squares and serve with cold beer, Mexican rice, beans, sour cream or cornbread.