Place the shredded cabbage in a small glass bowl. Pour liquid from the can of jalapeños over the cabbage, toss well, and allow to marinate for about 10 minutes, while you prepare the tacos.
Fill a 2-quart saucepan with water and bring to a boil. Add the whole tomatoes and allow to simmer for 1 minute. Remove the tomatoes and discard the water. Peel the tomatoes, cut in half, and remove the seeds. Add the tomato pieces to a blender, along with the clove of garlic. Make a puree.
Add the vegetable oil to a 9-inch skillet, and heat for about 1 minute over a medium flame. Add the tomato puree, and simmer for about 3 to 5 minutes until the sauce is reduced.
Divide the chicharrónes between all of the tortillas. Top with the warm sauce, sliced jalapeños, marinated shredded cabbage, and crumbled queso fresco.