In a bowl or large zip-top bag, combine the olive oil, soy sauce, lime juice, minced garlic, chili powder, cumin, smoked paprika, black pepper, and salt. Mix well.

Add the flank or skirt steak to the marinade. Seal and refrigerate for at least 30 minutes, or up to 4 hours.

Heat a skillet over medium-high heat with a tablespoon of butter. Add the corn kernels and let them cook undisturbed for 2-3 minutes until charred. Stir and cook for another 2 minutes. Remove and let cool.

In a medium bowl, combine the cooled charred corn, mayonnaise, sour cream, crumbled Cotija cheese, red onion, cilantro, lime juice, chili powder, and garlic powder. Stir well and refrigerate until ready to use.

Preheat a grill or heavy skillet to medium-high heat. Remove the steak from the marinade and discard excess liquid. Grill the steak for 4 to 6 minutes per side, until it reaches an internal temperature of 130°F to 135°F for medium-rare.

Transfer the cooked steak to a cutting board, tent loosely with foil, and let it rest for 5-10 minutes.

Slice the rested steak very thinly against the grain.

Warm the flour tortillas in a dry skillet until pliable. Assemble the tacos by placing sliced steak in each tortilla and topping generously with the street corn salsa. Garnish with extra cilantro and serve with lime wedges.