Place beef kabobs on grill preheated to medium-high. Grill 3 to 4 min. per side, or until an instant-read thermometer inserted into meat registers 160˚F (71˚C) for medium; or cook to desired doneness. Brush kabobs with barbecue sauce. Transfer to clean plate; remove beef and vegetables from skewers. Let rest 5 min, then chop beef and vegetables into bite-size pieces.
To make each quesadilla, spread 1 tbsp (15 mL) pesto on ½ of one side of a tortilla wrapper. Layer onto the pesto side of wrapper, ¼ cup (60 mL) cheese, ¼ of tomato slices and ¼ of chopped kabob mixture. Fold over tortilla wrapper to cover filling. Repeat process with other 3 tortillas.
Place folded tortillas on grill and cook 1 to 2 min., per side; until cheese starts to melt and tortilla turns crispy. Transfer to chopping board; slice each into 4 wedges. Serve with sour cream for dipping, if desired.
Substitute beef kabobs with Sensations by Compliments Chicken Kabobs with Vegetables.