I need help to identify this insect. Found on my squash plants. Would like to know if I should leave them alone or to kill them, organically of course.

It is a leaf-footed bug nymph, and it is definitely a foe.
You can use properly diluted orange oil to kill them, and you can -- and should -- crush them (adults and nymphs) whenever you find them.

Here is more info: http://insects.tamu.edu/fieldguide/aimg65.html

There are hundreds of different kinds of leaf-footed bugs, but all are leaf chewers.

One note, get familiar with your predatory bugs: http://www.ipm.ucdavis.edu/PMG/NE/assassin_bugs.html

as the nymphs of assassin bugs have somewhat the same body shape (but different coloring) as the leaf-footed bugs.

There's also an organic spray called Spinosad. It only kills what chews on the leaves so it will not harm beneficials or bees.

Thank you so much for your help I really appreciate your knowledge and especially the generous sharing of it. Again thanks a bunch.