how can you pump to help yourself go faster?

Rather than pumping try side sliding. Here's a quote from the link down below to help:

"Reaching the Waves.

If you are having trouble getting out to waves without sinking you may want to try Side-Slipping. This can be hard to master but its worth it. Basically, while your speeding over the water out toward the wave, you turn your board sideways so that your toes are pointed out toward the ocean. If you trim it just right, you will lose speed at a much slower rate. When you get near the wave, turn your board back to its normal position and ride like you normally would."

The other trick that will help you to catch those waves is by picking the right wave. Check out this quote too:

"Wave Selection: The main thing to look for when learning to ride waves is NOT the wave you will be riding. You should be looking at the water in front of the wave you will be riding. Is it moving? How fast? In what direction? Water that is moving toward the shore helps keep you afloat. Water that is being sucked out to sea is almost impossible to float over. You need to run for the right waves in order to be a good skimboarder."

You'll probably benefit from checking out the entire site. It has lots of great information about skim boarding.

Good luck with catching those waves..