Bring a stockpot of water to a boil with 3 teaspoons of the salt.
Quarter the squash and zucchini lengthwise and cut into 1/4-inch slices.
Heat the olive oil in a large saute pan over medium-high heat and saute the shallot and garlic 1 to 2 minutes, until translucent. Add the squash, stir to coat, season with the remaining salt and the pepper and cook 2 to 3 minutes, until lightly golden but still crisp.
Slowly add the wine, scraping up the bits. Stir in the butter until melted, toss in the tarragon and turn the heat to low.
Cook the pasta 2 to 3 minutes and lift it straight into the pan with the tomatoes. Toss over medium heat, adding pasta water to loosen if you like.
Top with the arugula and big dollops of ricotta and garnish with nutmeg.