In a medium bowl, whisk together soy sauce, brown sugar, sesame oil, garlic, and ginger until sugar is dissolved.
Add sliced steak to the marinade, toss to coat, and refrigerate for 20 minutes.
Rinse jasmine rice until water runs clear, then cook according to package instructions.
In a small bowl, combine mayonnaise, Sriracha, and lime juice; whisk until smooth and set aside.
Heat a heavy-bottomed skillet or wok over high heat with a teaspoon of oil.
Remove steak from marinade and sear in batches for 2 to 3 minutes per side until caramelized and cooked through.
Divide cooked rice among four bowls.
Arrange seared steak, sliced cucumbers, and kimchi over the rice.
Drizzle the spicy cream sauce over the steak and garnish with green onions and sesame seeds.