In a medium bowl, whisk together peanut butter, rice vinegar, honey, and soy sauce. Tip: If the sauce is too thick, thin it out with a splash of water (1–2 tablespoons) until it reaches a pourable consistency.
Place the cucumber slices in a large serving bowl and pour the peanut sauce over the cucumbers and toss gently to coat.
Sprinkle with crushed peanuts and garnish with sliced green onions.
Chill for 10–15 minutes (optional) for extra crunch and flavor melding.