If making your own egg roll wrapper dough: Add flour and salt to a medium wide mouthed bowl. Give a quick mix and then create a well.
Crack the egg into the well and then use a fork to whisk the egg, incorporating the edges of the well while whisking. Slowly add the warm water, one tablespoon at a time, mixing more and more of the dough as you add.
Continue until a shaggy dough is formed. Remove dough from bowl and place on a floured surface and knead for 2-3 minutes until a smooth only slightly tacky dough is formed. If dough is too sticky, add more flour. If dough is too dry and not holding together, add a bit more water.
Cut dough into 4 equal parts. Wrap the dough you're not rolling out in plastic wrap and set aside.
Flour a large cutting board or counter, and use a rolling pin to roll dough out as thin as you can. Flour rolling pin and surface as needed to prevent sticking. Once a large thin disc is rolled out, gently transfer it to parchment paper. Use a knife to or pastry wheel to cut long 1/4 - 1/2 inch wide strips and then cut across to cut 2-3 inch long strips. Set parchment paper aside.
Repeat with the rest of the dough. Or make as much as you want and store the rest of the dough in the fridge or freezer to use another time.
If using pre-made egg roll wrappers, just cut then into the 2-3 inch by 1/4 - 1/2 inch strips.
Add 3-4 inches of vegetable or peanut oil to a pan and heat over medium until it reaches 375°F or use the wooden spoon test to check to see if oil is ready (see recipe notes).
Add dough strips to oil and fry for about 30-60 seconds then turn and let fry another 30-60 seconds until golden brown. Remove with slotted spoon and let drain on paper towel-lined plate. Repeat with all dough strips.
Ladle soup into bowl, garnish with diced green onion and top with crispy egg roll wrapper strips and enjoy!