In a sauce pan: place pork, garlic and enough water to cover. Bring to a boil, turn to low and simmer until meat is tender. Drain, rinse and set aside.
In a large pot set on medium-high, place water, cumin and salt. Bring to a boil. Turn down heat, simmer.
In a microwave heat proof container (I use Pyrex measuring cup) melt shortening. While hot, whisk in enough flour to make a smooth semi-thick paste. (The thicker you make this, the thicker your chili will be.)
Turn the burner down to medium-low. Using the whisk, add the flour/shortening mixture to pot of seasoned water. Whisk until smooth. From now on, stir frequently from the bottom of the pot - LOW heat only.
Add sliced onion to pot - stir.
Add tomatoes and/or tomatillos to pot - stir.
Add green chili and jalapenos to pot - stir.
Add drained meat to pot - stir.
Heat through and serve - as a dip, as a sauce over burritos, tamales, etc., or in a bowl with a spoon.