Yes and yes, but be careful not to squeeze too much power out of it. Start with a lighter load and check the temperature of the transformer after a while. It it gets too hot for your hand touch then it's too much power.
Another thing one can do with a transformer is to wire the primary and secondary in series, turning it into an autotransformer. With the mains power feeding the original primary winding, the output voltage from the primary+secondary will be either higher or lower than the primary voltage, depending on whether the secondary is connected in phase or in opposite phase relative to the primary. Measure with an AC voltmeter, and if it's the opposite of what you want then swap the secondary wires.
E.g., I've used a 115V-24V transformer (originally intended for a boiler's thermostat system) to get an output of about 90V (115 - 24) to run a fan slower and quieter. In this case the power running through the transformer is only a portion of the total, so, e.g., a 24W transformer (24V 1A) can handle a fan that uses about 100W.
