Brown pork well, until juices are released. In blender, put tomatoes and jalapeno and enough water to cover. Blend until juice.
Put juice from blender and chopped green chiles in a large sauce pan. Add browned meat. Add water as needed for gravy. Add garlic powder to taste and tomato paste to color as desired. Bring to a boil, then cover and simmer one hour.
If desired, thicken with flour paste. Add salt at the very end - cook for a few minutes to cook in salt.