Trim the tough ends off the asparagus and cut into 2-inch pieces. Thinly slice the radishes into rounds for maximum crispness and visual appeal. Chop the green onions into thin rounds, separating white and green parts. Roughly chop the fresh mint leaves. Coarsely chop the pistachios so they're still chunky enough to provide texture. Set all prepped ingredients aside on a cutting board or in small bowls.
Mince the garlic cloves finely. In a small bowl, whisk together the minced garlic, Dijon mustard, honey, and apple cider vinegar until combined. Slowly drizzle in the olive oil while whisking constantly to create an emulsion that will coat the vegetables evenly. Squeeze the fresh lemon juice and add it to the dressing. Season with salt and black pepper to taste. I like to let the dressing sit for a minute after whisking so the flavors can meld before using it.
Place the spinach in a large bowl as your base. Add the prepped asparagus, sugar snap peas, radishes, and chopped green onion whites from Step 1 on top of the spinach. Sprinkle the chopped pistachios and mint over the vegetables. Pour the lemon vinaigrette from Step 2 over the entire salad and toss gently but thoroughly until all components are well coated and the spinach begins to wilt slightly from the dressing and the warmth of the vegetables. I prefer to dress the salad just before serving to keep the vegetables as crisp as possible.
Taste the salad and adjust the seasoning as needed—add a squeeze of fresh lemon juice if it needs more acidity, or a pinch of salt if the flavors need brightening. Divide into serving bowls or plates and enjoy immediately while the vegetables are still crisp and the greens are at their most vibrant.