In a bowl, whisk together the miso paste, honey, water and soy sauce. Set aside.
In a large bowl, whisk the salt and rice flour together until the salt is fully combined.
Add the chicken to the mixture and toss the chicken in the rice flour until each piece is fully coated. They should look like they're coated lightly in snow. If using corn starch, whisk it with egg whites to form a paste, then coat the chicken in the mixture.
Over medium high heat, generously season a pan with oil. Make sure the entire surface is coated. Once the oil is shimmering, place each piece of chicken onto the surface and make sure they do not overlap. Let them sear for 2-4 minutes, until the side on the pan turns golden grown, or light golden brown. Flip and let the chicken cook for another 4-5 minutes, until the other side is golden brown. Feel free to also cook the other sides of the chicken to develop color, but it's not necessary as long as your chicken meat is fully cooked through (should be white inside).
While the chicken is cooking, put a sauce pan on medium heat to make your sauce. If you're using flour, add the butter and let it melt. Then, add the flour and whisk, to create a roux. Add 1/4th of the miso water mixture and mix until smooth and paste-like. Then, add the rest of the liquid and continue to whisk until fully incorporated. There should be no clumps! It will also begin to thicken. If you're using corn starch, add the corn starch directly to your miso water mixture and mix until fully combined. By adding the starch to the liquid, you're making a slurry (which is basically a fancy word for corn starch water, but feel free to google if you want to understand this more!) Add the mixture to a sauce pan and cook until thickened, mixing intermittently to ensure that there are no clumps.
Return back to your chicken and lower the heat of the pan once the chicken is fully cooked. (or just move your chicken to a new pan.) We want to make sure the pan isn't too hot because it could burn our sauce (honey = sugar = burns quickly.)
Add the sauce mixture to the pan and toss the chicken in the sauce. Turn off the heat.
Plate the salad and then top with the chicken. Feel free to add more sliced scallions and sesame seeds! Serve immediately or eat the leftovers tomorrow. This tastes great hot, at room temp, or cold.