Cut the chuck flap beef into bite-sized pieces.
Slice paprika, onion, and zucchini into appropriate sizes.
Season the beef with salt and pepper.
Skewer the beef, paprika, onion, and zucchini alternately on skewers.
Heat oil in a pan and preheat.
Grill the skewers over medium heat, turning them back and forth until cooked.
Lightly brush with sesame oil and sprinkle sesame seeds to finish.