Whisk together the vinegar, honey, orange juice and some salt and pepper to combine. Slowly whisk in the olive oil until emulsified. Set aside.
Heat a charcoal or gas grill to high for direct grilling. Brush the figs with some olive oil, season with salt and pepper and grill, cut-side down, just until slightly charred. Remove to a plate.
Toss the mizuna with some of the vinaigrette. Transfer the mizuna to a platter and arrange the figs over top. Sprinkle with the feta and pistachios and drizzle some of the remaining dressing over top. Serve at room temperature.