Cut pepper into 1/4" strips and thinly slice onion.
Heat a tablespoon of oil in nonstick skillet on medium-high heat. Add 1/4" strips of pepper and onion and stir to cook through. Cook until soft, about 8 minutes.
Add a cup of water and turn heat to high setting. Boil until water is evaporated and veggies are tender, about 4 minutes. Remove from stove, season with salt and pepper and cover so they stay warm.
Heat grill/grill pan on medium-high heat. In bowl, combine cumin, garlic, and the rest of the oil to make thin paste. Spread on steak and rub into both sides of meat.
Season the steak with salt and pepper, grill 5 minutes each side for medium rare. Remove from heat and allow the steak to rest for 5 minutes. Thinly slice across grain. Serve with peppers and onions.
If you do not have poblano peppers available, use a bell pepper with a dash of hot sauce. For extra flavor, allow steak to marinate at room temp for 30 minutes before cooking.