Heat the sesame oil in a medium saucepan over medium-high heat. Add the sesame seeds and cook, stirring, until golden, about 1 minute. Stir in the rice, then add 1 3/4 cups water; bring to a boil and cook until most of the water evaporates, about 8 minutes. Cover, reduce the heat to low and cook until tender, about 12 more minutes; remove from the heat and let stand until ready to serve.
Meanwhile, preheat the broiler. Thread the pork onto 4 long metal skewers, leaving space between each piece; season with salt and pepper. Place the asparagus on a baking sheet and toss with the vegetable oil and ponzu sauce. Push the asparagus to the side of the pan and add the pork skewers.
Broil the pork and asparagus, turning once or twice, until the pork is browned and cooked through and the asparagus is charred in spots, 8 to 10 minutes. Divide among plates and drizzle the pork with the pan juices; serve with the sesame rice and lemon wedges.
Ponzu sauce is a tangy Japanese condiment. If you can't find it, use low-sodium soy sauce and a splash of lemon juice.