Mix all the marinade ingredients together in a large resealable plastic bag. Add the steaks and refrigerate for 1 to 4 hours.
Heat a cast iron griddle over medium-high heat. Remove the steaks from the marinade and wipe off the excess. Cook the steaks for 3 minutes per side for medium-rare. Remove from griddle to a cutting board and tent with foil. Let rest while you cook the peppers.
Heat a large cast iron skillet over medium-high heat and add the olive oil. Add the poblano, red bell pepper, and onion and saute until tender and softened. Season with salt and pepper, to taste. Remove to a bowl.
Wipe out the cast iron skillet. Toast the tortillas, until warm and slightly puffy. Remove and wrap in a clean kitchen towel to stay warm.
Cut the steak across the grain into thin 1/2-inch strips. Arrange on a large platter with the vegetables, cilantro, lime wedges, sour cream and a small bowl of salsa verde, if desired.