Cut the spaghetti squash in half and scoop out the seeds. Place in a microwave-safe dish and cook for 10 to 20 minutes until done or cook the squash your favorite way. When it's done, shred into 'noodles', place in a colander lined with paper towels, and set aside.
While the squash is cooking, whisk together all ingredients for the sauce except for the warm water. After everything is mixed, add the water, one tablespoon at a time, whisking until smooth. Set the sauce aside.
Prepare the tofu by pressing it to remove the water. Slice the tofu lengthwise through the center, then slice into about 24 small rectangles. Lay the slices on a paper towel and cover with another towel. Press with your hands to remove more water.
Heat 2 tablespoons of canola oil in a large sauté pan over medium-high heat. When hot, add the tofu and cook until golden brown, about 2 minutes per side. Flip and continue cooking until all sides are crispy and golden. Remove the tofu and set aside.
In the same pan, heat 1 tablespoon of canola oil. When hot, add the red bell pepper and stir-fry for a few minutes until they start to get seared and soften. Add the tofu back into the pan and cook for a minute to heat it again.
Turn the heat to low, pour in the peanut sauce, and quickly stir everything together, ensuring all the tofu and peppers are covered. Don't let it sit too long or the sauce will start to congeal.
Add the spaghetti squash 'noodles' and toss to incorporate, ensuring everything is fully covered in sauce. Remove from heat as soon as it's mixed together. Serve immediately over a bed of arugula.
