What should I do about these kids?(sort of long)?

Don't put your hands on them under any cirstances, that's ault, which is what they are doing to you. If it was me... I'd press charges, spitting is a big no no... they could end up getting you extremely sick, there are plenty of saliva communicable diseases and in some cases it could considered as attempted murder or man slaughter (that's if they have a communicable disease) I know hep can be transmitted thru saliva. So, I'd seriously consider pressing charges.