Marinate the Steak: In a bowl, whisk together vegetable oil, sesame oil, soy sauce, brown sugar, garlic, ginger, and black pepper. Coat the flank steak thoroughly with this marinade, cover, and let it marinate for at least 30 minutes.

Prepare the Spicy Cream Sauce: While the steak marinates, whisk together mayonnaise, sriracha sauce, lime juice, and honey until smooth. Set aside for later.

Cook the Steak: Preheat a grill pan over medium-high heat. Cook the flank steak for about 4-5 minutes per side or until the internal temperature reaches 130°F for medium-rare. Let it rest for 5 minutes.

Assemble the Rice Bowls: Place cooked jasmine rice in bowls, slice the rested steak against the grain, and place it over rice with green onions, carrots, and cucumber.

Drizzle with Sauce & Serve: Drizzle the spicy cream sauce over the bowls, sprinkle with toasted sesame seeds if desired, and serve immediately.