To prep the shrimp: Whisk together the wine, garlic, red pepper, salt and lemon juice. Slowly pour in the olive oil. Add the shrimp and toss to coat. Let stand at room temperature for about 20 minutes.
Meanwhile, pickle the onions. Combine in a medium sauce pot, red wine vinegar, sugar, red pepper flakes, salt, black pepper and water. Bring to a boil and pour over the onions. Let cool and then refrigerate.
In another small saucepan, place the 1 cup of balsamic over medium heat and reduce until the vinegar becomes syrupy, about 10 minutes. Remove from the heat and let sit at room temperature until ready to use. May need to reheat for use.
Have the grill preheated to medium-high.
Drain shrimp and reserve the marinade. Wrap 1 prosciutto strip around each shrimp and place 2 shrimp on each skewer, leaving a little room between each shrimp. Brush each of the skewers with some of the reserved marinade and place on the grill. Grill the shrimp until the prosciutto is crispy and the shrimp turn opaque and are cooked through, about 3 minutes per side.
In a large bowl, dress the arugula and the pickled onions with remaining balsamic, a splash of olive oil, salt and pepper. Transfer to a serving dish and top with the shrimp skewers. Drizzle the balsamic reduction over the top.