In MEL you can simply select faces (and verts, cv's etc) by using the object name plus .f[1] for face 1 or .vtx[2] for vertex 2 etc.
e.g.
select pCube1.f[0];
will select face 0 on pCube1.
You can also select more than one at a time by typing:
select pCube1.f[0:10];
which selects faces 0 to 10 of pCube1.
Richard