Is it permissible for an employee to submit a forged employment contract for his wife in order to obtain an accompanying leave for her, after his request for his own leave was rejected by the employer?

If work regulations guarantee your right to leave without any restrictions or conditions, then there is no blame upon you for using stratagems to obtain it. Lying is permissible to obtain a right if it is the only means to do so. However, if the regulations do not guarantee your right or stipulate conditions that have not been met, then it is not permissible for you to do so.