Combine the lemon juice, lemon zest, olive oil, Dijon mustard, sugar, sea salt, and freshly cracked pepper, to taste together in a bowl. Whisk until well combined.
Bring a pot of water (seasoned with a bit of salt) to boil over high heat. Add the sugar snap peas and cook for 30 seconds. Drain and plunge into ice water to stop the cooking process and to ensure the color will stay bright green.
Pour the sugar snap peas into the bowl with the vinaigrette and toss to coat evenly. Season with sea salt and freshly cracked pepper, to taste, if desired. Enjoy.