Bring a large pot of salted water to a boil. Fill a large bowl with ice water. When the water is boiling, drop the sugar snaps into the pot and cook for 1 minute. Drain the sugar snap peas and plunge them into the ice water.
While you are waiting for the water to boil, make the vinaigrette: In a large bowl, combine the olive oil, balsamic vinegar, rice vinegar, Dijon mustard, honey, shallot, salt, and pepper.
Drain the cooled sugar snap peas, shake off any excess water, and add them with the onion, cucumbers, dill, and mint to the dressing in the bowl. Toss to combine. Taste, adjust seasonings as needed, and serve.
Notes
You can make this salad with raw sugar snap peas, or if they aren’t absolutely young and perfect, a quick blanching makes them amazing. Blanching involves bringing a pot of salted water to a boil, dumping the sugar snaps in the water for 60 seconds, then draining them and plunging them into a bowl of ice water you have at the ready. When the peas are cool, they are ready to be drained and eaten or used in a recipe.
If your sugar snap peas are young and don’t have a thick string running down the side of them, you can just trim off the tips on both edges, cutting off just the very end to keep as much of the bean intact as possible.
If they are more mature, they may have a string running down one or both sides of the bean, where the halves are joined, and that should be removed by peeling it off as you remove the tips. Find a child or helpful guest or family member to help you with this slightly tedious but sometimes necessary task.
Make-Ahead: You can make this up to 2 days ahead of time and store it well-sealed in the refrigerator. The beans will soften a bit more in the dressing, and their bright green color may fade a bit, but it will still be delicious.