Spicy Beef Salad

1. Pat the beef dry and season with salt and pepper. Heat vegetable oil in a grill pan or cast-iron skillet over medium-high heat. 2. Sear the beef for 3-4 minutes per side for medium-rare, or to your preferred doneness. Let it rest for 5 minutes before thinly slicing against the grain. 3. In a large bowl, whisk together fish sauce, lime juice, and sugar for the dressing. 4. Add the sliced beef, shallots, mint leaves, chopped coriander, cucumber slices, tomato wedges, and sliced chilies to the bowl. 5. Toss gently to combine all ingredients with the dressing. 6. Taste and adjust the seasoning if needed. Serve immediately as a light meal or appetizer.