Combine brown sugar, soy sauce, ginger, fish sauce, and garlic in a resealable plastic bag.

Add steak to the bag, toss to coat, and refrigerate for at least 2 hours to marinate.

Preheat a deep fryer to 375 degrees F.

Line a sheet pan with a cooling rack or paper towels.

In a large bowl, combine 1 cup rice flour and all-purpose flour.

Add soda water and whisk to form a tempura batter.

In a separate dish, combine the remaining 1 cup rice flour and 1 tablespoon salt.

Dredge potato slices in the rice flour mixture, then dip in the tempura batter.

Shake off excess batter and carefully place the fries in the fryer.

Cook until golden brown and tender, about 8 minutes.

Transfer fries to the prepared sheet pan and season with salt.

Repeat for the remaining fries.

Preheat a grill or grill pan to high heat and preheat the oven to 375 degrees F.

Remove the steak from the marinade and brush with canola oil.

Grill the steak for about 5 minutes per side.

Transfer the steak to a sheet pan and finish cooking in the oven until medium rare, about 7 to 10 minutes.

Transfer the steak to a cutting board, tent with foil, and rest for at least 5 minutes.

In a large bowl, combine julienned carrots, thinly sliced scallions, and thinly sliced Napa cabbage.

In a separate bowl, whisk together agave, rice vinegar, gochugaru, sesame seeds, fish sauce, and salt.

Add enough dressing to the slaw to lightly coat the vegetables.

Reserve the remaining dressing for another use.

Slice the steak and serve with the kimchi slaw and tempura fries.