Preheat grill to medium heat.
Prepare the zucchinis by trimming off the ends and cutting them into long, thin strips, about 1/4 inch thick.
In a mixing bowl, whisk together the peanut butter, soy sauce, honey, rice vinegar, sesame oil, ginger, garlic, and red pepper flakes.
Taste the sauce and adjust the seasoning, adding more red pepper flakes for more heat or honey for more sweetness.
Season the zucchini strips with salt and pepper and place them on the grill.
Grill the zucchini for about 2-3 minutes on each side, or until they have nice grill marks and are tender.
Remove the zucchini from the grill and place them on a serving plate.
Drizzle the spicy peanut sauce over the zucchini strips.
Garnish with chopped peanuts and green onions, if desired.
Serve immediately and enjoy the delicious and healthy grilled zucchini with spicy peanut sauce.