Heat grill. Spray bell peppers with nonstick cooking spray.
When ready to grill, place peppers on gas grill over medium-high heat or on charcoal grill 4 to 6 inches from medium-high coals. Cook 4 to 6 minutes or until crisp-tender and grill marked, turning occasionally. Remove from grill; let stand until cool enough to handle.
Reduce heat on gas grill to low, or spread out coals to reduce heat.
Spray 1 side of each tortilla with nonstick cooking spray. Place sprayed side down on work surface. Thinly slice bell peppers. Place 1/4 of peppers on half of each tortilla. Sprinkle each with 1/3 cup cheese and 1 tablespoon olives. Fold remaining half of each tortilla over filling.
Place folded tortillas on grill; cook 2 to 3 minutes or until bottoms are golden brown. Turn; cook an additional 2 to 3 minutes or until tortillas are golden brown and cheese is melted. Serve with salsa and sour cream.