Tap to click is usually on by default, but I know that I am not the only one that disables it on all my computers to avoid clicking all over the place. In most desktop environments (Unity, MATE, Gnome, KDE..), the Mouse and trackpad system settings panel lets you turn off tap to click, but in LXDE, there is no such option in the Keyboard and Mouse settings.
However, there is a method that should work in LXDE on most distros that use it (Lubuntu, LXLE, Debian with LXDE, MintPPC etc) Unfortunately, this only works if your trackpad uses the synaptics drivers. This is how you do it: Open the LXDE menu > Preferences > Customize default applications for LXSession. Choose the Autostart tab. Choose config-only from the drop-down menu where it says “Disable autostarted applications?”. Write “@synclient MaxTapTime=0” in the text field next to the “Add” button and hit the button. You will now see “@synclient MaxTapTime=0“ in the bottom of the list of “Manual autostarted applications”. Log out and log in. Now tap to click should be disabled.