Combine the rice, 2 cups of water, and a pinch of salt in a medium saucepan. Bring to a boil, then stir, reduce heat to very low, and cover. Cook for 20 minutes, until the rice is tender and the water is absorbed. Set aside, covered.
In a small bowl, whisk together the soy sauce, sherry, brown sugar, rice vinegar, sesame oil, and cornstarch. Set aside.
Season the pork tenderloin generously with salt and pepper. Heat the half of the canola oil in a large sauté pan over high heat. Add the pork and cook, turning occasionally, for 5-7 minutes, until the edges begin to brown and the pork is just cooked through. Transfer to a plate and set aside.
Add the last teaspoon of canola oil to the pan, and sauté the shallots until soft, 2-3 minutes. Add the asparagus and cook for 1 minute. Stir in the snap peas. Add 2 tablspoons of water, and scrape up any browned bits from the bottom of the pan. Add up to 2 more tablespoons of water if there are still a lot of browned bits. Sauté the vegetables until the asparagus and sugar snap peas are crisp-tender and bright green. Add the garlic, ginger, and crushed red pepper flakes, and sauté for another 30 seconds. Add the reserved soy sauce mixture, and fold in the cooked pork. Toss to coat in the sauce, and cook, stirring, until the vegetables are glazed and the sauce has thickened, just a minute or 2 longer.
Serve hot, with the rice.