Mix rice, 500 ml water and 1⁄2 teaspoon salt in a saucepan. Cover and soak overnight. Bring rice to a boil, uncovered. Cook half covered over low heat for 40 minutes. Remove from heat; leave to cool. Loosen rice occasionally with a fork.
Heat 3 tablespoons oil in a nonstick pan over medium heat. Cook brinjal about 10 minutes, turning occasionally.
Add garlic and cook 2 minutes. Remove pan from heat, leave to cool.
Combine ajvar, 2 tablespoons lemon juice, remaining 2 tablespoons oil, chili flakes and mint in a large bowl; season with salt and pepper to taste. Mix in cooked rice and tomatoes. Season with remaining 1 tablespoon lemon juice and salt and pepper to taste.
Line a serving plate with lettuce. Top with salad, brinjal, feta and olives.