"Chłopcy dotknęli pingwina."

Translation: The boys have touched the penguin.

[HelbentForleder]

I sure do hope this isn't euphemism.

[br0d4]

"dotknąć" [to touch] besides of literal (touch with ones finger) can mean to offend, to insult.

[fiorass]

Yes, but you can't say "Dotykam cię" while meaning "I offend you"/"I insult you".
You can use it only describing one's feelings. Same as in English "I feel touched" (emotionally affected, moved), with the only difference that in Polish we use it to describe only negative feelings - emotionally affected as in offended or insulted.

[br0d4]

Not quite. While I agree with your samples of 1-st person singular present tense (nobody would say "Ja dotykam" in the meaning "I offend sb.") - the phrase is in past tense, which changes a bit the perspective. See:

• "Dotknąłem nauczycielki, znaczy, jej rękę" - "I have touched the teacher, I mean, her hand" - but "Dotknąłem nauczycielkę moją wypowiedzią" - "I have offended the teacher with my statement".
• "On dotknął Pingwina" - "Pignwin" is capitalised, what suggest that this is a ninckname of a person, so it may mean both "He has offended Pingwin" and "He has touched Pingwin". Without capitalisation "On dotknął pingwina" it is rather clear that an animal could not be offended (unless in a fairy-tale), so we would understand it as a physical touch, hence "He has touched the/a penguin".

[Euhan1]

They had better leave Gotham in a hurry!

[Ubeogesh]

Is the ę in dotknęli sound any different as opposed to if it was a plain e?

[br0d4]

If you go to a theatre - then yes, there is.

But if you listen to casual speech - then no, there is not.

[torronoir]

How would you say " the boys were touching the pinguin"

[deactivated user]

the boys touched the penguin

[Jellei]

That's another accepted answer.