Trim both ends off zucchini; cut in half lengthwise. Cut a thin slice off the backs so each half sits flat. Scoop out the pulp, leaving a 1/4-inch shell. Finely chop the pulp; set aside.
Place the zucchini halves in a microwave-safe dish. Sprinkle with 1/4 teaspoon each salt and pepper. Cover and microwave on High until tender-crisp, 3 to 4 minutes. (Alternatively, steam in a steamer basket over 1 inch of boiling water in a large skillet or pot.)
Whisk oil, vinegar, shallot and the remaining 1/4 teaspoon each salt and pepper in a medium bowl. Add tomatoes, cheese, basil and the reserved zucchini pulp; toss to combine. Divide the filling among the zu-canoes.
1 vegetable, 1/2 high-fat meat