Pulse Transformer Vs Normal Coil & Core
It could be that their recommending Pulse, the manufacturer, for your transformer supplier all transformers are just coils and cores. It could be that they are saying that Pulse have designed a transformer to work specifically for this application. By using a reworked microwave transformer you could end up destroying the tool as microwave transformers work at low frequencies. What you probably need is a SMPS check this out:

https://www.pulseelectronics.com/application_support/switching_power_supply_devices/