Combine 1/4 teaspoon salt and water in a medium saucepan; bring to a boil. Stir in barley; cover, reduce heat, and simmer 30 minutes or until liquid is absorbed.
Remove from heat; cover and let stand 5 minutes.
Spoon barley into a large bowl; cool slightly. Add mint, tomato, green onions, capers, and olives; stir well to combine. Combine remaining 1/4 teaspoon salt, 2 tablespoons lemon juice,red pepper and oil, stirring well with a whisk. Drizzle over barley mixture; toss gently to coat.