Heat grill to high (450° to 550°). Mix 2 tbsp. oil, the garlic, half the lemon juice, and the salt in a large bowl. Add vegetables and toss to coat.
Grill vegetables, turning once, until softened and grill marks appear, about 10 minutes.
Divide vegetables among 4 plates. Drizzle with remaining 2 tbsp. oil and the rest of lemon juice. Sprinkle with oregano. Serve with hummus, olives, and pita.