To a medium bowl, add all ingredients, whisk to combine; set aside.: The moment you whisk the vinaigrette you'll notice the aroma of sesame oil and rice vinegar lifting, a fragrant, slightly nutty scent that signals the dressing is coming alive. Use a whisk to emulsify the olive oil and sesame oil into the vinegar and mandarin juice, watching the liquid transform from separated droplets into a cohesive, glossy vinaigrette. This texture matters because a well emulsified dressing clings to the pasta and greens rather than pooling at the bottom. If the dressing breaks, slowly whisk in a teaspoon of warm water to bring it back together. A common mistake is adding salt too early, which can mask the delicate citrus notes, so hold off final seasoning until everything is combined.
Note – You are only adding the juice from one can of mandarins to the vinaigrette. Add the mandarins to a separate very large bowl.: When you separate juice and fruit, the vinaigrette gets concentrated citrus flavor without the fruit making the bowl watery, and the whole fruits retain their shape and texture when tossed with warm pasta . Place the drained orange segments in a very large bowl so there is room to toss without smashing them. Overcrowding the bowl makes it hard to distribute dressing evenly and increases the chance of crushing the fruit, which would release excess liquid.
Cook pasta according to package directions, drain, and add it to the bowl with the mandarins.: As the pasta boils, watch for the moment when it yields to a gentle bite, al dente, which gives the best mouthfeel in a tossed salad. Drain thoroughly so the residual hot water does not dilute the vinaigrette, and transfer the warm pasta into the bowl with the mandarin oranges so the citrus juices mingle with the pasta surface. The warmth helps the pasta absorb some dressing, making the final texture more cohesive. Do not rinse unless you plan to serve fully chilled, rinsing removes surface starch that helps the dressing adhere.
While the pasta is cooking, to a large skillet add the sesame oil, olive oil, chicken, season with salt and pepper, and cook over medium-high heat for about 5 minutes, or until chicken is cooked through; stir and flip intermittently to ensure even cooking.: When the oils heat they will shimmer and release aroma; add the diced chicken and you should hear a gentle sizzle which indicates good contact and browning. Stir intermittently to form small golden edges, these little crusts lock in juices and deepen the savory flavor profile. Cook until pieces read opaque through the center, and if you slice into a piece it should have no pink core. A common error is crowding the pan which causes steaming instead of searing, so if pieces are too close, cook in batches or use a larger skillet. The cooked chicken will have a toasty scent that complements the dressing.
Add chicken and all cooking juices to the bowl with the mandarins and pasta.: When you pour the chicken and its pan juices into the large bowl, you'll notice a savory perfume that deepens the overall salad aroma. The warm juices help meld flavors with the pasta and fruit, slightly loosening any stuck dressing so everything combines smoothly. Toss gently so the heat from the chicken loosens the vinaigrette into the pasta crevices. Avoid vigorous tossing which can break the mandarin oranges into mush; instead use a folding motion for even coating and to preserve texture.
Add the peppers, carrots, cucumbers, additional one can of mandarins (drain juice and discard), spinach, add the vinaigrette, stir and toss to combine and coat evenly.: At this stage the bowl becomes a collage of colors and textures, and you should hear the soft rustle of the spinach as it wilts slightly when mixed with warm components. Pour the vinaigrette over everything and fold gently, allowing the dressing to cling to the pasta and vegetables. The crunch of diced red bell pepper and shredded carrots will contrast with the tender pasta and soft mandarin oranges . If the salad looks dry, add a splash more rice vinegar or a drizzle of olive oil, but add small amounts to avoid over dressing. A typical misstep is overmixing which bruises delicate produce, so stop once everything is evenly coated.
Taste the salad and make any additional flavor adjustments such as more salt, pepper, sugar, vinegar, cayenne (doesn’t make it hot but adds flavor), etc. and either serve immediately or chill before serving.: Tasting is the final, essential act where balance is achieved. I pay attention to the interplay of sweet, salty, and acidic notes and tweak in small increments, noting how the flavors settle after a few minutes. If you plan to chill, remember cold dulls flavors slightly, so adjust seasoning a touch higher than if serving warm. One common error is over-salting early; always taste after tossing and again after chilling to decide if more seasoning is needed.