Step 1Whisk the soy sauce, oyster sauce, and 1 tablespoon each brown sugar and vegetable oil in a shallow dish. Add the steak, turning to coat. Cover and marinate for 30 minutes at room temperature or up to 8 hours in the refrigerator (remove from the refrigerator about 30 minutes before grilling).

Step 2Make the dipping sauce: Whisk the lime juice, cilantro, fish sauce, red pepper flakes, shallot, and remaining 2 tablespoons brown sugar in a medium bowl. Cover and refrigerate until ready to use.

Step 3Preheat a grill or grill pan to medium-high and oil the grates. Toss the green beans with the salt, ½ teaspoon pepper, and the remaining 1 tablespoon vegetable oil.

Step 4Arrange the green beans in a grill basket or on the grill pan in a single layer. Cook until tender and slightly charred, 3 to 5 minutes per side. Transfer to a bowl and keep warm.

Step 5Remove the steak from the marinade and pat dry; season with the remaining ½ teaspoon pepper. Grill, turning, until charred, 6 to 7 minutes for medium-rare.

Step 6Transfer the steak to a cutting board and let rest at least 5 minutes. Slice and serve with the dipping sauce, green beans, and rice.