Prepare the grill for indirect grilling, heating one side to low and leaving one side with no heat. Maintain grill temperature at 200° to 225°.
Place the wood chips on hot coals. Place a disposable aluminum foil pan on unheated side of grill. Pour 2 cups water in pan. Coat grill rack with cooking spray, and place on grill. Place tomatoes and pepper on grill rack over foil pan on unheated side. Close lid; cook 50 minutes. Remove tomatoes and pepper from grill; discard stem from pepper.
Place tomatoes, pepper, lime juice, marjoram, and garlic in a food processor; process 1 minute or until smooth. Pour mixture into a medium bowl; stir in onion, cilantro, and salt. Cover and chill at least 45 minutes before serving.