Truncate table using resource model in Magento 2

You can truncate table using DB Adapter and table name.

/** @var \Magento\Framework\DB\Adapter\AdapterInterface $connection */
$connection = $model->getResource()->getConnection();
$tableName = $model->getResource()->getMainTable();
$connection->truncateTable($tableName);

Alternatively you can get DB Adapter and table name from collection, but resource model rather.

/** @var \Magento\Framework\DB\Adapter\AdapterInterface $connection */
$connection = $model->getCollection()->getConnection();
$tableName = $model->getCollection()->getMainTable();
$connection->truncateTable($tableName);