Combine the burghul and boiling water in a large bowl. Stand for 1 hour. Drain and squeeze the burghul dry.
Meanwhile, whisk together the lime juice, oil, cumin, oregano and a pinch of salt in a large bowl. Stir in the tomatoes, corn, capsicum, spring onions and coriander. Add the drained burghul and toss to combine. Stand for at least 1 hour. Serve chilled or at room temperature.