Hard boil eggs. Cool, remove shells, and cut into quarters. Set aside 12 quarters for garnish.
Squeeze 3 tbsp juice from lemon and reserve. Add lemon rind to water in which eggs were cooked along with dill stems. Heat to boiling on high; add shrimp. Reduce heat to simmer and cook for 3 minutes or until shrimp are just cooked. Drain and rinse under cold water. Discard lemon rind and dill sprigs.
In same pan, cook potatoes with enough cold water to cover. Add 1 tsp salt. Heat to boiling on high, cover, and reduce heat to simmer 15 minutes until potatoes are tender. Drain.
While potatoes cook, cook snap peas and peas 2 minutes in boiling water. Drain well.
Whisk yogurt, mustard, 1 tbsp lemon juice, and 1/4 tsp each salt and pepper in a large bowl. Add hot potatoes, onion, celery, shrimp, eggs, and half of chopped dill. Fold gently until combined.
In another bowl, whisk vinegar, oil, remaining 2 tbsp lemon juice, and 1/4 each salt and pepper; add all peas and remaining dill. Toss until well coated.
Spoon shrimp salad into center of serving platter, then spoon pea mixture all around. Garnish with reserved egg quarters and serve immediately.