Prepare an indoor or outdoor grill over medium-high heat. Sprinkle skirt steak on both sides with salt, pepper and and 1 1/4 teaspoons chipotle powder. Whisk 1 1/2 tablespoons olive oil and 1 tablespoon lime juice in 11x7-inch glass dish. Add meat and turn to coat. Marinate for 30 minutes.
Meanwhile, brush green onions and corn with 1 tablespoon oil and sprinkle with salt and pepper. Grill vegetables until slightly charred, turning occasionally, about 2 minutes for green onions and 7 minutes for corn. Cut the corn from cob and transfer the kernels to a bowl. Chop green onions and add to corn. Stir in cilantro, chives, lime zest, and remaining 1/4 teaspoon chipotle powder, 1/2 tablespoon oil, and 1 tablespoon lime juice. Season relish to taste with salt and pepper.
Grill the skirt steak to desired doneness, about 2 1/2 minutes per side for medium. Transfer to work surface; let rest 5 minutes.
Char tortillas over an open flame.
Thinly slice the skirt steak across grain. Divide skirt steak and juices equally among tortillas. Spoon corn mixture over each and serve.