Poached Salmon With Avocado Sauce

Name: Poached Salmon With Avocado Sauce
Ingredients: 2 8-ounce skinless salmon fillets (preferably wild), halved crosswise; Kosher salt, freshly ground pepper; 20 fresh tarragon leaves, torn; 1 quart vegetable broth; 2 cups stringed trimmed sugar snap peas or snow peas; 2 ripe avocados, halved, pitted; 1 cup plain low-fat yogurt; 1 tablespoon (or more) fresh lime juice; 1/2 teaspoon ground cumin; 4 cups arugula; 20 grape or cherry tomatoes, halved; 1 tablespoon minced shallot; 1 tablespoon plus 1 teaspoon olive oil; 2 tablespoons thinly sliced fresh chives; 4 lime wedges