Heat oil in a skillet over medium heat
Cut corn tortillas into triangles
Fry the tortilla pieces until crisp
Remove and drain excess oil
Make a salsa roja or salsa verde
Simmer the salsa in the skillet
Add the fried tortillas to the salsa
Toss until lightly coated
Cook briefly until softened but not soggy
Top with crumbled queso fresco
Add crema
Add sliced onions
Add avocado
Add fried eggs or shredded chicken if desired
Serve immediately