1. Lightly mist a large skillet with cooking spray and bring over medium heat. Add the diced onions and cook for a couple minutes until the onions start to turn translucent. Add the ground beef and hamburger seasoning and cook, breaking up with a spoon or spatula, until the meat is brown and cooked through. Drain any liquid from the pan and discard.
2. Transfer the meat to a microwavable mixing bowl and add the ketchup, mustard and chopped Laughing Cow cheese wedges. Stir together and then heat in the microwave on high for 1 minute to soften the cheese. Stir again, mashing the cheese wedges, until the mixture is well combined and the meat is coated. Add the shredded cheddar, pickles and tomatoes and stir until well combined.
3. Preheat the oven to 425. Line a baking sheet with aluminum foil and lightly mist the foil with cooking spray.
4. Pour water into a small dish and set aside. On a clean, flat surface, place an egg roll wrapper, corner facing toward you (like a diamond) and place a scant ¼ cup of the meat mixture on the center of the wrapper. Spread the mixture in a horizontal line from the left corner to the right corner of the wonton wrapper, leaving ½ inch or so of space on each side. Fold the bottom corner closest to you up over the ingredients and give it a 90 degree roll. Fold the side corners in and tuck them as you give the filled section another 90 degree roll. Dip your finger in the dish or reserved water and lightly wet the edges of the remaining top corner of the wrapper. Finish rolling the filled egg roll over the wet corner so that it adheres. Use your finger to wet and seal the seam on the outside. Place wrapped egg roll onto the prepared baking sheet. Repeat with remaining ingredients.
5. When all of the egg rolls are wrapped and on the baking sheets, lightly mist the tops with cooking spray. Bake for 14-16 minutes, flipping once halfway through, until the wrappers are golden brown.