COMBINE kimchee and half the barbecue sauce in bowl. Toss to coat; set aside.
FOR each serving: Brush 1 steak with 1 tsp. oil; season with 1/8 tsp. salt. Grill steak 4 min.; turn. Brush with 2 Tbsp. of the remaining barbecue sauce. Cook 3 min. or to desired doneness. Let rest before thinly slicing.
GRILL 2 tortillas. Fill each with steak and 2 Tbsp. kimchee mixture.