I haven't seen it myself but don't I wish I could... What I know:
-it was broadcast in 1990 on French tv (which means it dates from 1990 tops), but it was most probably American
-it was described to me as scary and disturbing
-the bad guys are faceless children that hatch from zucchinis

Invasion of the body snatchers from 1978?

Best I can come up with (even going to page 2 of google) is The Pod People.

@jd1984 It could be The Pod People from 1983 but that's a French-Spanish movie. My money's on IotBS with Donald Sutherland, Leonard Nimoy and Jeff Goldblum among others. Unless @purplepumpkin mis-remembered the year in which case it could be the 1993 remake The Invasion.

Ok so I've shown the synopsis and movie posters to the person who told me about that movie and while it's definitely not Pod People it could very well be Invasion of the Body Snatchers!!! The one from 1978. (So the key element, zucchini, was misleading as they didn't remember it quite right... @karboll that is an impressive guess!) I'm going to find it online and show them screenshots to be sure :D

@purplepumpkin Thank you, I'm a bit of a horror and sci-fi lover. Once it's about people coming out of cucumbers or pods it's usually those. They're great movies, even the remakes, and thanks to you I found out there's one I haven't seen from 2007.