Preheat grill to 450° to 500° (high) heat. Soak skewers for 30 minutes.
Stir together cumin, red pepper, and 1 1/2 tsp. salt. Thread steak onto skewers. Brush steak with 1 Tbsp. oil; sprinkle with salt mixture. Grill, covered with grill lid, 1 1/2 to 2 minutes on each side or to desired degree of doneness.
Whisk together peanut butter, coconut milk, 2 Tbsp. lime juice, and 1 1/2 Tbsp. soy sauce.
Whisk together 1/4 cup peanut butter mixture and remaining 2 Tbsp. canola oil, 1 Tbsp. lime juice, and 1 Tbsp. soy sauce. Toss mixture with slaw, cilantro, and remaining 1/2 tsp. salt. Serve slaw and beef skewers with remaining peanut sauce.