It's almost a sure bet that folks ascending the kegging learning curve will overcarb at least one keg.
Disconnect the gas completely, then relieve the head pressure in the keg (either using a manual PRV or pushing down on the gas poppet). Repeat often over at least a 24 hour period.
Then set your regulator for 10~12 psi, hook up the beer line, hook up the gas line, MAKE SURE THE BEER LINE IS COLD before proceeding, then try drawing a pint.
If it's still foamy, disconnect everything again and continue the degassing procedure until you get the beer tamed.
Note that this assumes you don't have a beer poppet or QD problem that is restricting the beer flow so severely that all you can get out of it is foam. If your faucet is actually "spitting" foam, that may be the real cause of your problem...