Jaccard each steak 10–12 times (or poke with fork 30–40 times). Cut into 4 equal pieces. Season both sides generously with salt and let rest for 15 minutes.
In a blender, combine the remaining ingredients. Blend on high until a smooth paste has formed.
Place the steaks in a gallon-sized bag and pour in the marinade from the blender. Seal the bag and place it in the refrigerator for at least 4 hours but preferably overnight.
Heat your grill to high. Oil the grates very well before grilling. Grill each steak for roughly 3-4 minutes per side. Be sure to reapply marinade as you cook them. Cook the steaks until they have an internal temperature between 130℉ and 140℉ (54-60℃). Allow the steaks to rest for at least 10 minutes before slicing.
Dice each steak into ½" (1.25cm) cubes.
To build the tacos, re-warm the tortillas if needed. Spread on some mashed avocado, load it up with steak and top with drained pico. Fold and devour immediately.