Combine the cumber and 1/4 cup of seasoned rice vinegar in a small bowl; set aside.
Combine the red onion with 2 tablespoons of rice vinegar in a small bowl; set aside.
Combine the mayonnaise with the sriracha sauce in a small bowl and mix until well combined; set aside.
Combine the soy sauce, sugar, minced garlic, and sesame oil in a small bowl and whisk until well combined; set aside.
Cook the beef in a large skillet over high heat until any juices have evaporated and the beef begins to fry in it's own fat, 8-10 minutes.
Add the soy sauce mixture to the skillet and cook until nearly evaporated, about 2 minutes. Pour into a serving bowl.
To serve the lettuce wraps, serve the ground beef with butter lettuce leaves, marinated cucumber slices, marinated red onion, radish slices, sriracha mayonnaise, and fresh cilantro on the side. Everyone can make their wrap just they way they like it. Enjoy.