Bring a large saucepan of water to a boil. Cook pasta according to package directions, drain and rinse well under cold water.

Mix sesame seeds, 1 tablespoon cornstarch and salt in a shallow dish. Cut the block of tofu lengthwise into 8 thin "steaks." Pat dry with a paper towel, and press both sides into the sesame-seed mixture.

Heat 2 teaspoons canola oil in a large nonstick skillet over medium-high heat. Add the tofu and cook until golden brown, about 3 minutes per side. Transfer to a plate, cover and keep warm.

Wipe out the pan. Heat the remaining 2 teaspoons canola oil. Add ginger, garlic and chiles and cook, stirring, until fragrant, about 30 seconds. Add snap peas and cook, stirring, until beginning to brown, about 2 minutes more. Add pineapple juice, bring to a boil and cook 2 minutes. Whisk the remaining 1 teaspoon cornstarch and soy sauce in a small bowl until smooth. Add to the pan and cook, stirring, until the sauce is thickened, about 1 minute. Reduce heat to low, add pineapple, sesame oil and the noodles; toss to coat with the sauce and cook until heated through, about 1 minute. Remove the chiles. Serve the noodles with the tofu.

To remove the stem and strings at the same time from sugar snap peas, hold the stem between your thumb and index finger, snap and pull down.