In bowl, stir black beans with pineapple, ¼ cup (60 mL) BBQ Sauce and vinegar. Place in 8 x 8-in. (20 x 20-cm) foil pan and cover tightly with foil (or make a double-thick foil packet large enough to seal in mixture).
Place covered foil pan (or packet) on grill preheated to medium-high. Cook 10 to 15 min., until bean mixture is heated through. Remove foil pan (or packet) from grill.
Toss pork medallions with remaining BBQ sauce. Grill 3 to 4 min. per side or until just cooked through. Grill naan bread 2 to 3 min. per side or until toasted and marked. Remove pork and naan from grill. Cut each naan into 8 wedges.
Wearing oven mitts to avoid steam, carefully open foil pan (or packet). Stir in green onions and cilantro. Divide bean mixture onto 4 plates. Top with pork medallions and serve with naan wedges.
Top bean mixture with dollops of sour cream or sprinkle with shredded Cheddar cheese.