Thinly slice the flank steak across the grain into 1-inch-wide strips.
In a medium bowl, whisk together the soy sauce, rice wine vinegar, honey and Chinese five-spice powder. Add the sliced steak and toss to combine.
Thread the steak onto wooden or metal skewers. (If using wooden skewers, soak them in water for 30 minutes prior to using them.)
Cook the kabobs over medium-high heat on a grill or stovetop grill pan, flipping them once, for about 5 minutes or until they reach your desired doneness.
While the kabobs cook, combine the yogurt, cucumbers, garlic, mint and lime juice in a small bowl and stir to combine. Taste and season with salt and pepper.
Serve the beef kabobs with the yogurt sauce for dipping.