Basic understanding

Cheers
Im looking at a MULTICOMP - MCF/Y9615F transformer.
It says:
Secondary Voltages:2 x 15V

Does that mean that i can get 1 x 30V ? or is that a no-go ?

IMO, you have the option of getting 2-15V outputs or 1-30V output. Generally, this means you have a 30V secondary with a center tap at 15V.

What he said or... you have two 15 volt secondaries that can be paralleled for 15 volts at a higher current or series for 30 vlts and half the current. The secondary likely will have 3 or 4 wires. Wait.....

Here is your data sheet. You have dual secondaries per the data sheet so either parallel for 15 volts or series for 30 volts.

Ron