In a large bowl, whisk together vegetable oil, sesame oil, soy sauce, brown sugar, minced garlic, grated ginger, and black pepper until combined. Add flank steak, ensuring it is fully coated in the marinade. Cover the bowl and refrigerate for at least 30 minutes or up to overnight.

While the steak marinates, cook jasmine rice according to package instructions until fluffy. Thinly slice green onions, shred carrots, and slice cucumber. Set vegetables aside.

In a small bowl, combine mayonnaise or Greek yogurt, sriracha, lime juice, honey, and salt. Whisk until creamy and smooth. Adjust sriracha for desired spiciness.

Heat a skillet over medium-high heat. Remove flank steak from marinade and sear for 3-5 minutes on each side until the internal temperature reaches 125-130°F for medium-rare. Let it rest for 5-10 minutes before slicing.

Divide the fluffy jasmine rice among serving bowls. Top with sliced flank steak, green onions, shredded carrots, and cucumbers. Drizzle with spicy cream sauce and finish with lime juice or extra sriracha.