How to Make It
Stir together shallot, lemon zest, lemon juice, garlic, salt, and pepper in a medium bowl; let stand 5 minutes. Whisk in honey and mustard. Add oil in a slow, steady stream, whisking constantly. Set aside.
Stir together peas and 1 teaspoon of the salt in a medium saucepan. Add water to cover by a depth of 1 inch. Bring to a boil over medium-high, skimming foam that rises to the top. Reduce heat to medium-low. Partially cover; simmer until tender, 15 to 25 minutes. Drain; transfer peas to Vinaigrette in bowl. Let mixture stand, stirring occasionally, until cool, about 10 minutes.
Stir cherry tomatoes, lemon balm, parsley, and remaining 1⁄4 teaspoon salt into cooled pea mixture. Arrange sliced heirloom tomatoes on a serving platter. Top with pea mixture; sprinkle with pepper. Serve immediately.