Discard soft outer leaves of cabbage and thinly slice on a mandolin. Discard or eat the core. Transfer shredded cabbage to a large mixing bowl.
Add sliced cucumbers, thawed peas and green onion and toss lightly to combine.
Drizzle salad with 3 to 4 Tbsp oil, 2 Tbsp cider vinegar, 2 Tbsp white vinegar and toss to combine. Before serving, sprinkle with salt and pepper to taste (start with 1/2 tsp salt and 1/4 tsp black pepper and go up from there). You can also add more vinegar to taste if your cabbage was larger.
Notes
You can use a knife to slice cabbage, but it is easiest to achieve the fine/thin strips of cabbage with a mandolin. Also, anytime you use a mandolin, protect your hands with safety gloves.