Salt and pepper ground beef then brown in a skillet. Drain.

In a small bowl mix fish sauce, Sriracha and water.

Add Sriracha mixture to beef and cook on med/high heat, stirring until water has evaporated. (This will only take a minute)

Remove from heat. Stir in zest of lime, lime juice, green onions and cilantro.

Serve in lettuce leaves.

This can easily be doubled to serve 4.