Wash the radishes thoroughly and slice them very thin, about 2 mm thick, aiming for uniform slices that will cook evenly and stay crisp.
Mince the garlic cloves finely, releasing their fragrant aroma and ensuring quick, even flavor distribution during cooking.
Heat a wide skillet or wok over medium-high heat until shimmering, then add the vegetable oil. Swirl to coat the pan evenly.
Add the minced garlic to the hot oil and cook for about 30 seconds until fragrant, with a warm aroma filling the air and the garlic just beginning to turn golden.
Toss in the sliced radishes and stir quickly to coat them in the garlic and oil, then cook for 2-3 minutes, stirring constantly until they just start to soften and turn translucent around the edges.
Pour in the soy sauce and stir to evenly distribute, cooking for another minute so the radishes absorb the salty, umami flavor.
If you like spicy heat, sprinkle chili flakes over the radishes now, stirring quickly to release their aroma, and cook for about 15 seconds.
Remove the skillet from heat and drizzle the toasted sesame oil over the radishes, tossing gently to coat and add a rich, nutty aroma.
Transfer the stir-fried radishes to a serving plate, then sprinkle with sliced green onions for a fresh, sharp bite and a pop of color.
Serve immediately while hot, enjoying the vibrant crunch and peppery zing that makes this simple dish so lively and satisfying.
