How to Make It
In a small bowl, mix the paprika with the shallots, 3 tablespoons of the olive oil and 1 1/2 tablespoons each of salt and pepper. Rub the marinade all over the steaks and refrigerate for 2 to 6 hours. Let return to room temperature before grilling.
Meanwhile, preheat the oven to 375°. In a pie plate, bake the hazelnuts for about 8 minutes, until lightly browned. Transfer to a clean kitchen towel and rub the nuts together to remove the skins. Coarsely chop the nuts.
In a medium saucepan of salted boiling water, blanch the peas until crisp-tender, 2 to 3 minutes. Using a slotted spoon, transfer to an ice bath to cool. Add the asparagus to the boiling water and cook until crisp-tender, 1 to 2 minutes; transfer to the ice bath to cool. Drain the peas and asparagus and pat dry.
Light a grill or preheat a grill pan. Scrape the marinade off the steaks. Grill the steaks over moderately high heat, turning occasionally, until lightly charred all over and medium rare within, about 10 minutes. Transfer to a cutting board and let rest for 5 minutes.
In a large bowl, toss the watercress with the peas, asparagus, hazelnuts, rhubarb, ginger, lemon zest, lemon juice and the remaining 3 tablespoons of olive oil. Season with salt and pepper. Slice the steaks across the grain and serve with the salad.