Prepare Basic Mexican Red Chili Sauce and set aside.
Combine eggs, milk, and salt, and beat well.
In a large skillet (I prefer cast iron), heat oil over med-high heat and add onions pieces. Cook onions until they begin to turn quite brown and swell up.
WHOLE EGG VERSION:
No need for skim milk...drop the eggs into separate quadrants of the skillet while still hot and lower the heat to medium. Cover with a lid to trap the heat so that the top of the eggs will cook. When the outer edge of the eggs begin to crisp up and the egg whites are no longer clear, add the chili sauce, re-cover and let simmer until the yolks are cooked to your liking.
SCRAMBLED EGG VERSION:
While oil is still hot, pour egg mixture into skillet, then reduce heat to med-low.
Slightly move cooked outer edge away from the side of the pan to allow for eg liquid to filter down to the bottom. Avoid stirring the egg or mixing it too much. You may want to pierce the center of your egg mixture to allow for the egg in the middle to get cooked as well.
When the egg is mostly cooked, divide it into pie sections and turn sections over to cook the other side. After one or two minutes, pour Basic Mexican Red Sauce over it. Cover and simmer until the egg is puffy and has absorbed some of the sauce.
Serve with soft, warm corn tortillas. It is also great to garnish it with minced fresh cilantro and sliced avocado.