How to Make It
Heat a large cast-iron skillet over medium-high heat. Sprinkle steaks evenly with paprika, 1/8 teaspoon fleur de sel, and 1/4 teaspoon black pepper. Add 1 1/2 teaspoons oil to pan; swirl to coat. Add steaks to pan; cook 4 minutes on each side or until desired degree of doneness. Remove steaks from pan; let stand 10 minutes.
Add remaining 1 tablespoon oil to pan; swirl to coat. Add onion wedges; cook 2 minutes on each side. Add poblanos to pan; sauté 4 minutes, stirring occasionally. Remove from heat; cover and let stand 5 minutes. Stir in remaining 1/4 teaspoon fleur de sel and remaining 1/8 teaspoon black pepper. Arrange onion mixture on a platter. Cut steak across grain into thin slices. Arrange steak over onion mixture; sprinkle evenly with sel gris. Serve with lime wedges.