Place the brick of udon in a bowl of hot tap water to defrost and loosen. When soft and loose, drain well.
In a small bowl, whisk together the curry paste, coconut milk (or chicken stock), brown sugar, and 2 tablespoons water. Taste and adjust seasoning if needed.
Heat up a bit of oil in a skillet over medium high heat and cook the pork, breaking up pressing down into the pan. Let cook, without moving, until pork is golden and browned, about 3 minutes. When browned, flip and break up in to small pieces, cooking until no longer pink, about 1 more minute.
Turn the heat down to medium. Add the snap peas. Cook for 1 minute, stirring until snap peas are bright green. Add the udon and sauce and cook, stirring, until the noodles are coated and glossy. Garnish with the green onions, cilantro and lime if desired and enjoy!