Garden help anyone??

The kids and I were so excited to plant our garden this year! We got everything planted and were very proud of it. Unfortunately we have some kind of pests that are eating/ruining our plants. The first batch of tomato plants and cucumber plants had their leaves all eaten off so nothing was left but the stem. So, we replanted and covered them with some cages that we jimmy rigged out of some wire fencing stuff we had. It has square openings that are about 1" by 2". It is not stopping these pests! Last time all the leaves disappeared so I figured they were eaten by some animal. This time I am seeing a few leaves that have been taken off still mostly in tact lying near the plants. The kids and I are REALLY frustrated because we all love garden tomatoes and cucumbers! If you have any idea what this is or what we can do to protect what's left of our plants PLEASE share! We are willing to try almost anything. This has never happened to us in our garden before so I'm stumped. Of course this has to happen this year too since we told the kids that they were in charge of most of the work in the garden this year...I hope someone can help us before it's too late for our lovely tomatoes and cucumbers.