Like all weapons, you can obtain the Kreska form different ways. The first one you have is to buy it in the Arsenal of your ship or through the Market Console for 175 Platinum. This way you also obtain an Orokin Catalyst already installed as well as an extra weapons slot in your Arsenal.
The second way to obtain the Kreska is completing the Corpus lab research in your Dojo. To do that you will need to contribute with the required resources and wait three days until it is completed. After that you can buy the Blueprint in the Lab to be able to craft the Kreska machete in the Foundry of your ship.