Bring a large pot of salted water to a boil and cook the whole grain spaghetti according to package directions until al dente, then drain and set aside.
In a small mixing bowl, whisk together the coconut aminos, cashew butter, rice vinegar, and red pepper flakes until the sauce is smooth and emulsified.
Heat the avocado oil in a large skillet or wok over medium-high heat.
Season the shrimp with sea salt and add them to the skillet, searing for about 2 minutes per side until they turn pink and opaque, then remove them from the pan and set aside.
Add the toasted sesame oil to the same skillet, then toss in the minced ginger, garlic, chopped bok choy, and sliced bell pepper.
Sauté the vegetables for 3 to 4 minutes until they are tender-crisp and the aromatics are fragrant.
Add the cooked spaghetti to the skillet along with the seared shrimp and the prepared sauce.
Toss everything together for 1 to 2 minutes over heat until the noodles are well-coated and the sauce has slightly thickened.
Garnish the stir-fry with sesame seeds and thinly sliced green onions before serving warm.