Use a chef's knife and cutting board to thinly slice the radishes into rounds, creating uniform, crisp slices. Arrange the slices on a clean plate for easy handling.
In a small mixing bowl, combine the rice vinegar, honey (or sugar), and a tiny dab of fish sauce. Whisk until the mixture is well blended and slightly emulsified, with a fragrant aroma emerging from the dressing.
Slowly drizzle the olive oil into the dressing mixture while whisking continuously to create a smooth, well-integrated vinaigrette. Taste and season with salt and pepper as desired.
Place the arrowleaf arugula in a large serving bowl. Add the sliced radishes on top of the greens.
Pour the dressing over the radishes and arugula. Toss gently with tongs or two spoons until all ingredients are evenly coated, ensuring the radishes and greens are glistening.
Serve immediately in individual bowls or on a platter, showcasing the vibrant radishes and fresh greens with a light, savory dressing that highlights their crisp textures.
