Cut the skirt steak into ¼” pieces and place in a mixing bowl.
In a medium bowl, whisk together the lime juice, lemon juice, orange juice, apple cider vinegar, soy sauce, garlic, salt, chili powder, cumin and cayenne pepper.
Pour the marinade over the sliced steak and cover. Place steak in the refrigerator to marinade for at least 3 hours. I often marinade overnight for maximum flavor.
When you’re ready to cook your carne asada, turn your Instant Pot onto Sauté mode. Add the olive oil and ½ cup of onions and cook until they start to become translucent (about 2-3 minutes).
Turn off your Instant Pot. Add the marinated skirt steak along with all of the marinade to the inner pan, close the lid and turn the Instant Pot on High Pressure for 6 minutes.
Once the time is up, use a natural pressure release for 15 minutes, then quick release any remaining pressure. Open the lid. Using tongs, transfer carne asada to a serving platter or bowl.
To serve, add carne asada to warmed tortilla, then top with pico de gallo, extra lime juice and/or other toppings of your choice (see below for ideas).