Cell was created from the cells of some of the galaxy's greatest warriors and has inherited many of their traits, such as Goku's techniques and Piccolo's inherent abilities!

Absorption

When Cell stabs someone with the sharp, pointed end of his tail, he can absorb that person's life force into himself for energy.
That's exactly what he did when he attacked Ginger Town, where he absorbed the entire population and powered up enough to be more than a match for Piccolo, even after fusing with Kami.

First Appearance: Tale 361 (VS a wealthy resident of Ginger Town)

In the case of absorbing his Android siblings, Cell can open the end of his tail wide enough to swallow his target whole.
He first used this gruesome ability to gobble up Android 17 and achieve his Second Form.

First Appearance: Tale 372 (VS Android 17)

Kamehameha

As fans well know, this is a Kame School technique developed by Kamesennin in which the user draws out and condenses the latent energy from inside themselves and releases it through their hands.
Cell is able to use this technique due to having Goku's cells integrated into his body, but since that particular cell data was from when Goku first fought Vegeta on Earth, this version of Cell's Kamehameha wouldn't have been powerful enough to stop Piccolo after he fused with Kami.

First Appearance: Tale 362 (VS Piccolo)

Taiyo-Ken (Solar Flare)

This technique, first used in the series by Tenshinhan, allows the user to release an intense flash of light that blinds their opponents.

First Appearance: Tale 364 (VS Piccolo)

Cell was able to regrow his tail in an instant after it was ripped off by Android 16.
This is a signature ability of Piccolo that Cell has inherited thanks to possessing his cell data.

First Appearance: Tale 371 (VS Android 16)

* All comic images are from the Japanese version.