To begin, pulse the cilantro, garlic, green onions, jalapeno, and cumin in the food processor until finely chopped, about 10 to 12 1-second pulses, scraping down the sides as necessary. Add the 1/4 c. oil and process until the mixture is smooth and resembles pesto, about 15 seconds, again scraping down the sides of the work bowl as necessary. Transfer 2 T. herb paste to a medium bowl. Whisk in lime juice, and set aside.

Using a dinner fork, poke each piece of steak 10 to 12 times on each side. Place the meat in a large baking dish and rub all sides of the steak pieces evenly with salt, then coat with the remaining herb paste. Cover with plastic wrap and refrigerate at least 30 minutes or up to 2 hours, maximum.

Scrape the herb paste off the steak and sprinkle all sides of the pieces evenly with sugar, salt, and pepper. Heat the 2 T. oil in a 12-inch, heavy-bottomed, nonstick skillet over medium-high heat until smoking. Place the steak in the skillet and cook the pieces until well browned, about 3 minutes. Flip the steak, and sear the second side until it is well browned, another 2-3 minutes.

Using tongs, stand each piece on a cut side and cook, turning as necessary, until all cut sides are well browned and the internal temperature registers 125-130 degrees on an instant-read thermometer, about 2-7 minutes. Transfer the steak to a cutting board and let is rest for 5 minutes.

Using a sharp chef's knife or carving knife, slice the steak pieces across the grain into 1/8-inch-thick pieces. Transfer the sliced steak to a bowl with the herb past-lime juice mixture you had set aside, and toss to coat. Season with salt. Spoon a small amount of sliced steak into the center of each warm tortilla and serve immediately, passing the toppings separately.