I just installed DB2 on a non-GUI Linux system

I have not used DB2 in years

1> Without installing a Windows client, what command can I invoke to create and configure a new table (or do I have to install the Windows client first)

2> What command do I execute to start an interactive SQL session ?

You can use putty to ssh into the Linux and use the command line interface. Just begin each command with db2:

db2 "select * from syscat.bufferpools"
or
db2 -tvf create_table.sql > create_table.out (assuming SQL is in create_table.sql file)

If you want a GUI interface from Windows, you can install IBM Data Studio, a free download from IBM (free registration may be required). You can also use the Control Center if you install the DB2 client for Windows (also free download), but you will need to make sure the adminstrative server is running on Linux for some Control Center functions to work. The Control is officially "depricated" but still works for most things, and sometimes better than Data Studio.