Slice the radish into 1/8-inch disks, then slice into thin sticks, about 1/8-inch.
Place radish sticks in a mixing bowl, add salt, and let it sit for 10 minutes.
Add green onion, jalopeño, flour, cornstarch, egg, and 3 tablespoon water. Mix well. If the batter seems to dry add more water. Adjust the amount of flour and water to your desired batter texture.
Heat 1-2 tablespoon of oil in a cast iron skillet over medium heat, add 1/4 cup of radish batter onto the skillet and spread thinly. Sprinkle a little bit of toasted sesame seeds on top. Fry for 2-3 minutes until the bottom get golden brown. Flip and fry for another 2-3 minutes.
To make soy lemon dipping sauce, mix soy sauce and lemon juice in a small mixing bowl. Serve the pancakes warm with soy sauce lemon juice dipping sauce.