No room in breaker box to wire submersible well pump in. What's the best way to do it?

It sounds like you are thinking about connecting wires directly from the mains (before any breakers in the existing service entrance) which sounds a bit sketchy, as the wire from there to the new box would have no protection if something shorted before the new breaker. Maybe, it might be easier/safer if you replace 4 regular breakers with 2 of the twin ones (the ones where (2) 15 or 20 amp breakers fit in the space of one regular one) then you will have 2 spaces left over which could fit the one for the pump.

No. Besides being against Code it would mean having to pull the meter and That You can not do! (Yeah yeah, I know you "can" you just shouldn't) lol

Depending on the brand of panel you have you should be able to make another 2-pole space by using one or more of the following: Wafer, piggy back, tandem or quad breakers. Take a picture of the interior of the panel to a building supply store. Someone there should be able to help you mix/match a combination to allow another 2-pole breaker.

That's what I need to do, take out 4 115v breakers & replace with 2 115v tandem breakers to open up a 230v space. I knew about tandem breakers but I also knew that with 230v breakers. every load needed it's own breaker since they are major loads. I had thought about a 230v tandem breaker but didn't know if they made those anyway.