Put the potatoes in a pot and cover with water by 1 inch; season with salt. Bring to a boil. Reduce the heat to medium and simmer until tender, about 8 minutes, adding the scallions during the last minute. Drain.
Meanwhile, season the turkey with the paprika, 1/2 teaspoon salt and a few grinds of pepper. Heat the vegetable oil in a large skillet over medium heat. Add the turkey and cook until browned and cooked through, about 3 minutes per side; remove to a plate.
Add the broth to the skillet, scraping the pan with a wooden spoon. Cook until reduced by half, about 5 minutes. Stir in the mustard and half of the butter. Season with salt and pepper; set aside.
Melt the remaining butter in the pot used for the potatoes over medium heat. Add the potatoes, 1/4 cup water, the peas, lemon zest, parsley and a pinch each of salt and pepper. Cook until the peas are tender, 3 minutes. Serve with the turkey, pan sauce and lemon wedges.