How to Make It
Combine wine, 1/4 cup each vinegar and oil, 1 tbsp. each garlic and pepper, 1 tsp. each salt and cumin, the oregano, and ground chiles in a large, resealable plastic food bag. If steak is in 1 long piece, cut in half crosswise; rinse, add to bag, seal, and turn to coat. Chill at least 4 hours or up to 1 day.
Preheat broiler. Halve, stem, and seed the poblanos. Lay skin side up on a baking sheet and broil 4 inches from heat until well charred, 6 to 7 minutes. Let stand 10 minutes, then peel and coarsely chop.
Heat grill to high (450° to 550°). In a large frying pan over medium-high heat, sauté onion and remaining 1 tbsp. garlic in 2 tbsp. oil until soft, about 5 minutes. Stir in beans and remaining 1/4 cup vinegar and 1 tsp. each pepper, salt, and cumin; turn heat to low.
Oil cooking grate well. Lift steak from marinade (discard marinade) and grill, turning once, until browned on both sides but still pink in the center (cut to test), 7 to 10 minutes total. Transfer to a board and let rest at least 5 minutes.
Meanwhile, add poblanos, red pepper, tomatoes, 3 green onions, and cilantro to bean mixture, and stir occasionally until warm. Slice steak on the diagonal across the grain and serve on warm bean salad. Garnish with more green onions if you like.
Note: Nutritional analysis is per serving.