How to have Landing Legs Opened by Default

You could put them on an Activation group and then go to the command pod or chip and turn the slider by the AG to on

This is a feature a few of us have requested in the suggestions section of the forums, along with customizable/procedural landing legs. The game already has customizable/procedural landing gear (wheels). Hopefully in a future update they'll add more in-depth landing legs features, and I hope they simultaneously add a property to set landing-leg parts to be fully-deployed on the launchpad in the part configuration menu in the editor. Let us know if you get it to work with the current version of SR2, because I'd love to know what works, I've tinkered a lot with landing legs to try and achieve this, but failed so far. :)

Also you have to go into tinker panel, and set the staging to none

make sure the landing legs are in a action group(there is a "landing legs" name by default). in the "part proprties" of the command pod/chip, there is a "edit activation groups" button, and you can select which action groups start "on" or "off" - it might take a second for them to lower...so im not sure if it will work if they need to be down to stand up immediately