How can we Delete mass Accounts from org using Dml operation in salesforce?

Hi Vikas,

You may use Batch Class to delete all records of Account sobject.

For Example :-

Global class BatchMassDeleteRecs Implements Database.batchable<sobject>{
global final string query;
global BatchMassDeleteRecs(string q){

query=q;
}

global Database.QueryLocator start(Database.BatchableContext BC){

return Database.getQueryLocator(query);
}
global void execute(Database.BatchableContext BC,List<SObject> scope){
delete scope;

}
global void finish(Database.BatchableContext BC){
}

}