Pat lamb racks dry with paper towel. Season with steak spice. Rub with 2 tbsp (30 mL) olive oil. Set aside. To make basting sauce for lamb, whisk together barbecue sauce, beer, 1 tbsp (15 mL) vinegar and 1 tbsp (15 mL) maple syrup. Set aside.
Toss asparagus with 1 tbsp olive oil. Set aside. To make dressing for asparagus, mix remaining olive oil, vinegar and maple syrup, plus the grainy mustard, salt and pepper. Set aside.
Place lamb racks on grill preheated to high. Cook 2 min. per side, or until browned. Move lamb to one side of grill, turning off burner directly under meat. Set heat on adjacent burner to medium. Cook 15 to 20 min. -- basting with barbecue sauce mixture in last 5 min. -- until internal temperature of lamb registers 145 °F (63°C) for medium-rare, or until desired doneness. Remove lamb from grill. Tent with foil 5 to 10 min.
Meanwhile, increase grill heat to medium-high. Grill asparagus, turning often, until tender, 5 to 8 min. Slice and plate chops. Serve alongside grilled asparagus drizzled with reserved dressing.