Poblanos are large, dark-green chiles that are surprisingly mild. They can be roasted, peeled, and seeded much like a bell pepper can.
Cut poblanos in half lengthwise; discard seeds and membranes. Place poblanos, skin sides down, on grill rack. Grill 15 minutes or until blackened. Place in a zip-top plastic bag; seal. Let stand 15 minutes. Peel and dice. Stir in cilantro, juice, 1/4 teaspoon salt, and 1/8 teaspoon black pepper.
Sprinkle steak with 1/4 teaspoon salt and 1/8 teaspoon black pepper. Place on grill rack; grill 8 minutes on each side or until thermometer registers 145° (medium-rare) or until desired degree of doneness. Remove from grill; let stand 5 minutes. Cut steak diagonally across the grain into thin slices. Serve with relish.
I'll make the relish and eat it with chips, but it's paired perfectly with the steak. The steak is overseasoned without the relish and it is fabulous! Personally, I double the relish recipe because it's so good it goes too fast!