It can be done but very carefully and obviously not recommended for the inexperienced. As you mentioned, due to lack of sole separate lubrication system, a two cycle engine can easily be destroyed (in a matter of seconds) due to lack of lubrication. So far the popular ways of doing this is with the use of seafoam additives. There are two ways to do it. Personally, I soak the cylinders with pure seafoam by spraying (3~4 sprays, aiming on all sides) it directly into the plug hole in each cylinder and manually rotating the flywheel to distribute it (of course you have to remove all plugs). Keep the engine full upright so as to prevent the seafoam from draining into the crankshaft alleys. Re-install the plugs and leave it overnight. Keep some of the seafoam in the spray bottle (any spray bottle as long as it can hold about 1/2 quart or less).
The next day make preps to start the engine. Leave the upper cowl off and remove the air covers on the carbs. Make sure nothing loose can get sucked in to the carbs while engine is running. Place a plyboard or some flat sheet metal (like those one used to catch oil drip under the car) under the LU spotted for the exhaust. This is so as to see how much carbon is blowing out of the exhaust when you de-carbon which will tell you when to stop. Start engine and warm it up, about 2~3 minutes. Using the tie bar or the control tower on the carbs' linkage rev up the engine but do not exceed ~3K rpm in short and intermittent fashion while spraying (a single spray of mist seafoam into each carb. Start with the top carb and intermittently switch with the bottom ones. Then watch how much carbon is spewing out of the exhaust. If exhaust is heavy on carbon, continue doing the same until it lightens up. Do not wait until the exhaust is totally light, as this is very dangerous for the motor. I'd say when the carbon dust coming out of the exhaust is like 50% less than the initial one, then it is time to stop.
Put everything back together and then pour in the left over seafoam into the fuel tank in right proportion, read directions. The above process is best done in warm weather that doesn't mean it cannot be done in cooler weather.
The other way of doing it is just to spray the cylinder with seafoam, soak it and treating the fuel tank with seafoam. Take the motor on the water, warm it up and run at WOT for about 5~10 minutes.