1) Currently ITR for the F.Y. 2017-18 will get processed. Is this the only period you were outside India. If yes then you would be resident in Indian and your global income is taxable in India.
2) what is the nature of your income?. If it is salary then you can not claim any expenses otherwise you can claim them. There is no correlation of VAT paid in Dubai and income tax in India.
3) You need to share more details for computation of total income earned by you in India during f.y. 17-18.
You can email me your docs at [deleted].