Combine chili garlic paste, lemon zest, ginger, garlic, sesame oil, brown sugar, and ponzu in a bowl and mix well to create the marinade.

Place flank steak in a plastic storage bag, add the marinade, remove air, and refrigerate overnight.

Preheat grill pan over medium-high heat.

Remove steak from marinade bag, removing as much marinade as possible and reserve 1/2 cup.

Season the steak with kosher salt and pepper.

Brush grill pan lightly with canola oil.

Grill steak for 2 1/2 minutes, rotate 45 degrees, and grill for another 2 1/2 minutes.

Flip steak and cook for an additional 5 minutes, rotating 45 degrees after 2 1/2 minutes.

Remove from grill pan and let rest for 10 minutes under foil.

Thinly slice steak against the grain.

Toss salad greens, red onion, tomato and avocado (if using) with vinaigrette.

Arrange salad on a platter.

Place a heap of fennel slaw in the center of salad.

Place sliced meat around the sides.

Drizzle meat with barbeque sauce and mango puree, ensuring sauce gets onto salad and slaw.

Puree mangoes in a blender.

Add rice wine vinegar and chili garlic paste and blend until incorporated.

Bring reserved marinade to a boil.

Lower heat and reduce by half (10 minutes).

Strain sauce (optional).

Add half of the mango puree and cook for 2 minutes.

Set aside the sauce and save the remaining mango puree for garnish.

Juice the lemon into a bowl.

Whisk in olive oil to create an emulsion.

Add honey, lemon zest, salt and pepper, and whisk until combined.

Slice fennel very thinly with a mandolin.

Combine fennel and dressing.

Let rest until ready to serve.

Re-season with salt and pepper, to taste.

Sprinkle with black sesame.