Wonton Balloons?

We experimented today to make pizza ravioli using wonton skins. We used sliced mozzarella/provolone cheese cut into quarters and pepperoni slices that we precooked to crisp them up and render some of the fat out of it. we put a slice of cheese, a piece of pepperoni, another slice of cheese and another pepperoni onto a wonton skin. Then we brushed the edges with water and sealed with another wonton skin making sure to get as much air out as possible. Into the hot oil they went and... MAN was that fast. The sauce is homemade using a 28 oz can of plum tomatoes and about 5 tsp of freshly ground pizza seasoning (we used McCormick). It was very good but I wish there was a way to keep them from puffing up so much. Anyone know of a way to keep these things from becoming tasty balloons?