Suggest A Proper Workspace For Coin Collections?

Wood is only a problem if it's unseasoned and used for long term storage. Most desks or tables will be waxed or varnished and made from old wood. Since you're presumably just using it to work on I can't imagine it will be a problem.

Damp in the air, things like cigarette smoke, salt if you live near the sea, how you store your coins and physically handling them are more of a potential risk than a table.

If you plan on actually storing your coins in the desk, the same principles (use well seasoned wood - mahogany is traditional - and allow any glues/ varnishes to fully dry before use) apply.

I store my coins (admittedly they are 350+ years old and most toned with age) in a traditional mahogany coin cabinet and have no concerns. I say that because I know the British Museum and dealers such as Spink and Baldwins in London use very similar cabinets and have done for the last hundred years or more.

I always wanted an old railroad roll top desk or something with lots of cubbyholes and drawers that could be closed and locked. I really like the desks with hidden compartments in them too. Someday...