Begin by marinating the flank steak. In a bowl, combine vegetable oil, sesame oil, soy sauce, brown sugar, minced garlic, grated ginger, and black pepper. Add the flank steak, ensuring it is well coated. Cover and let it marinate in the refrigerator for at least 30 minutes, or up to 2 hours for more flavor.

While the steak is marinating, prepare the spicy cream sauce. In a small bowl, mix together mayonnaise, sriracha sauce, lime juice, honey, and a pinch of salt. Adjust the spice level by adding more sriracha if desired. Set aside.

After marinating, heat a grill pan or skillet over medium-high heat. Remove the steak from the marinade and cook for about 4-5 minutes on each side, or until it reaches your desired level of doneness. Let it rest for a few minutes before slicing it thinly against the grain.

To assemble the rice bowls, divide the cooked jasmine rice among four bowls. Top each bowl with sliced steak, chopped green onions, shredded carrots, and cucumber slices.

Drizzle the spicy cream sauce over the top of each bowl. Serve immediately and enjoy!