In a large bowl, combine soy sauce, sesame oil, brown sugar, garlic, and ginger. Add the steak strips and mix well to coat. Allow to marinate for at least 30 minutes in the refrigerator.
Cook the rice according to package instructions. Keep it warm and set aside.
Prepare your vegetables while waiting. Slice the cucumber, chop the green onions, and slice the carrot.
Heat a grill pan over medium-high heat. Add the marinated steak and cook for 2-3 minutes on each side until done to desired doneness. Let the steak rest.
Assemble your bowl with a layer of cooked rice, a portion of grilled steak, and arrange fresh vegetables and kimchi on top.
Notes
Store any leftovers in an airtight container in the refrigerator and consume within 3 days. Reheat gently to ensure the steak remains tender and juicy.