Remove the egg roll wrappers from the package and cover them with a damp paper towel. This will keep the wrappers from drying out. Have a small glass of water ready for sealing the wrappers.
Place one egg roll wrapper on a cutting board. With damp fingers, moisten the outer edges of the wrapper. Place a piece of string cheese diagonally on one corner of the wrapper. Roll the cheese inside the wrapper to the halfway point and then fold the edges over the ends of cheese. Continue rolling, making sure the last corner seals. Place on a sheet pan, cover with a damp paper towel and repeat with the remaining cheese sticks.
Heat 1 inch of oil in a large skillet over medium heat.
While the oil is heating, warm the marinara in a saucepan over medium heat until warmed through. Place in a small serving bowl.
Fry the egg rolls until golden and crisp, about 1 1/2 minutes, turning regularly. Remove to a paper-towel-lined plate to drain excess oil.