1. Heat a grill pan over medium-high heat. Brush first 5 ingredients with 2 Tbsp. olive oil. Cook corn and onions in hot pan, turning occasionally, 5 to 6 minutes or until charred. Remove from pan. Cook peppers in pan 5 to 6 minutes or until charred. Remove from pan. Cook tomatoes in pan 2 to 3 minutes or until charred.
2. Rub steak with steak seasoning, and cook in pan over medium-high heat 5 to 6 minutes on each side or to desired degree of doneness. Remove from pan, and let stand 5 minutes. Chop steak.
3. Cut corn kernels from cobs, and place in a large bowl. Discard cobs. Chop onion, mini peppers, poblano, and tomatoes. Stir together garlic, next 2 ingredients, remaining 2 Tbsp. olive oil, and chopped vegetables. Serve steak and salsa in tortillas with desired toppings.