Begin by preparing the ingredients to ensure a smooth cooking process. Slice the chicken breast into thin strips to promote even cooking and tender texture. Mince the garlic finely to release its robust flavor throughout the dish. Julienne the fresh ginger into thin matchstick-sized pieces, allowing it to infuse the stir-fry with its aromatic warmth. Slice the onion and bell pepper thinly to maintain their crispness and add vibrant colors to the dish.

Heat vegetable oil in a large skillet or wok over medium-high heat until shimmering. Add the minced garlic and julienned ginger, stirring constantly for about 30 seconds or until they become fragrant. This step is crucial as it releases the aromatics' essential oils and flavors, setting the foundation for the dish.

Add the sliced chicken breast to the skillet, spreading it out evenly. Stir-fry the chicken strips for 5-7 minutes, stirring frequently to ensure all sides are cooked and no longer pink. Adjust the heat as needed to prevent burning while maintaining a steady sizzle.

Introduce the sliced onion and bell pepper into the skillet with the cooked chicken. Continue stir-frying for 3-4 minutes or until the vegetables reach a tender-crisp texture. Stirring continuously helps distribute the flavors evenly and ensures the vegetables are cooked just right.

Pour the soy, oyster, and sugar over the stir-fried mixture. Stir well to combine, coating all ingredients thoroughly with the savory-sweet sauce. Allow the dish to simmer for 2-3 minutes, allowing the flavors to meld together and the sauce to thicken slightly.

Transfer the Thai Ginger Chicken (Gai Pad Khing) to a serving platter or individual plates. Serve the dish hot over steamed jasmine rice, which absorbs the flavorful sauce. Garnish generously with fresh cilantro leaves to add color and a hint of freshness to each serving.