Slice the chard into 1/2-inch ribbons. Heat the oil in a large skillet over medium-high heat. Add the onion then cook until golden brown, about 4-5 minutes. To the onions, add the red pepper flakes and garlic. Stir for about 20 seconds until you are hit with the aroma of the garlic, then immediately add the broth or water, 1/2 teaspoon salt and the greens. Adjust the heat to medium-low then cover the skillet. Cook until the greens are almost tender. For Swiss chard this will be about 5 minutes. Spinach only takes about 2 minutes.

Uncover the pan, adjust the heat to medium-high, then cook until the juices have reduced significantly and merely glaze the greens. Taste and add salt if you think it needs it.

Serve with the corn tortillas, crumbled fresh cheese and salsa.