I have found the best way to season leftover rice in a "mexican rice" style - stumbled on this experimenting with a huge container of plain white rice left from a chinese food order today.

Put left over cooked white rice in a skillet with a few pats of butter, then mix in one tomato/chicken flavor bullion cube (I use maggi cubes), crumbled and 1/2 cup water. Let it simmer until the rice absorbs everything! It tastes like restaurant rice!

Be sure not to add any extra salt, the bullion has plenty!