This guide will tell you where to farm for the Spinning Needle and Seismic Palm in Warframe.
Spinning needle and Seismic plan can drop from certain infested enemies found in most missions with infested enemies in them.
The specific infected enemy you will look for is leapers, as they have a chance to drop either of the spinning needle or seismic pam mods. You can find the most leapers on Boethius on mercury or Tikal on earth, and you can run any node/mission you prefer.
Both the mods can drop from the leapers; however, they have relatively low drop rates. So it’s probably going to take you some time (a lot of leaper kills) before you can get the mods, so you must prepare yourself for a reasonably lengthy grind unless you’re super lucky and get it on the first try.