Preheat barbecue to medium-high. Cut each pepper into 6 to 8 wedges. Toss with 1 tbsp oil and salt. Place peppers on grill. Barbecue, covered, turning occasionally, until tender and grill marks form, 12 to 15 min. Remove to a serving platter. Whisk remaining oil with vinegar, oregano and garlic. Drizzle over peppers.