Bring a large pot of generously salted water to a boil. Add asparagus and snow peas; cook 30 seconds. Drain, rinse in very cold water, and drain well again.
In a large bowl, whisk together vinegar, lime juice, sugar, 1 tsp. salt, pepper, garlic, and shallot. While continuing to whisk, drizzle in oil until thickened. Add asparagus, snow peas, and parsley; toss to coat. Transfer to a serving platter, garnish with pepitas, and serve.