"A great Thai dish that is a favorite of my wife. Serve with jasmine rice, tomato and cucumber slices, and additional cilantro sprinkled on top. The contrast between the hot peppery beef and the tomatoes and cucumbers is great."
Stir fish sauce and garlic together in a large glass bowl. Add beef slices and toss to coat. Marinate meat for 15 minutes.
Heat 1 1/2 tablespoons sesame oil in a large skillet or wok over medium-high heat. Carefully add about 1/4 of the beef slices to the oil and saute until mostly browned, 3 to 5 minutes. Season beef with 1 tablespoon pepper and about 1/4 of the cilantro; continue cooking until the beef is no longer pink, 2 to 3 minutes more. Remove beef with a slotted spoon to a serving platter and repeat process with remaining ingredients.