I'm new to this game and was wondering if there was a way to run an open header (no muffler)?

I've seen them do it on airplanes. Not sure why, ...perhaps they were 4-strokes. On a 2-stroke, you get more power with a tuned exhaust than with a muffler or an open header. So I cna't really answer your question, but perhaps it doesn't need an answer? Can you be specific on "why" you ask?

You ABSOLUTLY need a tune pipe with a 2 stroke engine. This is the tune pipe who'll give all the power to your engine.

No tune pipe = no power

At the very least you'll need a muffler to use exhaust pressure to help get fuel to the carb. This is because the carbs are too big to give enough suction to draw fuel by themselves. Tuned pipes aren't necessary on a 2 stroke but a properly designed tuned pipe will give a large boost in performance (power) but only over a limited rev range. Older plane engines ran perfectly with an open exhaust but their carbs were much smaller then so had very good suction and didn't need exhaust pressure to the tank.

the pipe creates a chamber which creates backpressure for the 2 strokle which meters the fuel being entered into the motor, why would you wanna run a open header? thats pointless, 2 strokes sound horrible w/o a pipe, if your looking to make more noise run a single chamber pipe instead of a dual/two chamber pipe.