In an extra-large skillet cook beef over medium-high heat until meat is browned. Drain off any fat.
Add soy sauce, Asian chili sauce, and sesame oil to meat; stir to combine. Stir in slaw mix. Cook and stir over medium heat 2 to 3 minutes or until cooked through and slaw mixture is just wilted.
If using napa cabbage, trim each stem so you use the top leafy part of the cabbage. Spoon beef mixture onto the cabbage leaves. Top each with sweet pepper. If desired, drizzle with sriracha sauce. Fold cabbage leaves around filling. Serve immediately.