Bring a medium sauce pot of water to a boil. Add the rice noodles and cook until just tender, 8 to 10 minutes. Drain and rinse with cold water, then return to the pot and drizzle with the sesame oil, season with salt and pepper, and toss to coat.
While the water heats and the noodles cook, start preparing the stir-fry.

• Cut the tofu into ½-inch cubes.
• Divide the sesame seeds into two equal portions, one for the tofu and one for garnish.
• Divide the spicy chile-mango blend into two equal portions, one for the tofu and one for serving.
• Trim the root ends from the bok choy; cut the bok choy in half lengthwise, then crosswise into 1-inch-wide pieces.
• Cut the tomatoes in half.

In a wok or large frying pan over medium-high heat, warm 1 to 2 tablespoons neutral oil until hot but not smoking. Add the tofu and cook, stirring occasionally, until lightly browned and crisp, 3 to 5 minutes [see Chef’s Tip if cooking for 4 servings]. Transfer the tofu to a medium bowl, add half each of the sesame seeds and chile-mango blend, and stir to coat.
In the same pan used for the tofu, warm 1 to 2 teaspoons neutral oil over medium-high heat until hot but not smoking. Add the bok choy and tomatoes and cook, stirring occasionally, until just tender, 2 to 3 minutes. Stir in the stir-fry sauce and cook until fragrant and starting to evaporate, about 30 seconds. Remove from the heat.

Transfer the noodles to individual bowls and top with the tofu, bok choy, and tomatoes. Garnish with the remaining sesame seeds and serve the remaining chile-mango blend on the side.