Preheat the oven to 425 degrees F. Toss the poblanos and tomatoes with 1 tablespoon olive oil in a large bowl; season with 1/4 teaspoon salt and a few grinds of pepper. Spread on a parchment-lined baking sheet. Roast until tender and lightly browned in spots, about 25 minutes; set aside.
Meanwhile, bring 3 1/2 cups salted water to a boil in a medium saucepan. Whisk in the grits, then reduce the heat to a gentle simmer; cook, whisking constantly, until thickened, 5 to 7 minutes. Whisk in the cheese, butter and 1/2 teaspoon salt until smooth. Cover and set aside.
Heat the remaining 1 tablespoon olive oil in a large skillet over medium-high heat. Season the steak with salt, pepper and the chili powder. Add to the skillet and cook until browned, 3 to 4 minutes per side for medium rare. Transfer to a cutting board; let rest 5 minutes.
Toss the vegetables with the lime juice and cilantro. Slice the steak against the grain. Serve with the vegetables, grits and lime wedges.