Pour enough vegetable oil into a sturdy skillet or Dutch oven to reach 1 to 1.5 inches of depth.
Heat oil over medium-high heat until it reaches 350°F (175°C), or until a small piece of tortilla sizzles and floats immediately.
Working one at a time, carefully slide one corn tortilla into the hot oil and fry 10–15 seconds per side until soft and pliable.
Using tongs, fold the warmed tortilla in half and hold it in place, frying 30–60 seconds per side until golden brown and crispy.
Lift the shell out and drain on paper towels; while still warm, sprinkle salt on both sides.
Repeat steps 3–5 with remaining tortillas.
Let shells cool briefly, then fill and serve immediately or store cooled shells in an airtight container at room temperature for up to two days.