Move the kebabs over the drip pan, brush with olive oil again, close the grill, and cook until the pork is cooked through, about 10 minutes. Transfer to a rimmed baking sheet to rest. Remove the beans from the heat, add the zest from 1 lemon, and toss to combine. Halve the lemons crosswise and grill until nicely charred, 1 to 2 minutes. Place beans on serving platter, top with pork skewers and charred lemon halves, and serve.