Stir mustard seeds in small dry skillet over medium heat until beginning to pop, about 3 minutes. Transfer to small bowl; reserve.
Bring orange juice, sugar, 1/3 cup water, and orange peel to boil in large skillet, stirring until sugar dissolves. Reduce heat to medium; add mustard seeds, coriander seeds, caraway seeds, and ginger. Simmer until syrupy, 10 minutes. Add rhubarb; reduce heat to medium-low. Cover and simmer until rhubarb is tender but intact, 2 minutes. Using slotted spoon, transfer rhubarb to microwave-safe bowl; reserve.
Bring syrup in skillet to simmer. Add cabbage, vinegar, and wine; bring to boil. Reduce heat to medium, partially cover, and simmer until cabbage is soft and most of liquid is absorbed, stirring frequently, about 45 minutes. Season to taste with salt and pepper. Remove from heat.
Meanwhile, preheat oven to 425°F. Line rimmed baking sheet with parchment paper. Place salmon, skin side down, on prepared baking sheet. Brush salmon with olive oil; sprinkle with salt and pepper. Roast until salmon is just opaque in center, about 11 minutes. Rewarm reserved rhubarb in microwave just until warm.
Divide warm cabbage among 6 plates. Scatter arugula atop and around cabbage. Place 1 salmon fillet atop cabbage. Spoon dollop of yogurt atop salmon, then rhubarb.