So, I got the esp connected to a usb-serial adapter (pl2303) and used cutecom to send AT commands. It works :)

At fist i had trouble. I was getting a lot of "noise" on the line. The device was spitting "0x00" all the time. With the correct baud setting i was able to see some clear text messages in between.

A note on the interwebs led me to the solution: since i am using a sepparate PSU to power the esp i needed to have common ground between the psu and the serial-adapter. A bit of cable connected between them and everything worked lika a charm! :)