In a medium saucepan cook peas, covered, in a small amount of boiling salted water for 3 minutes. Drain and cool. Arrange peas, green onions, arugula, and Swiss chard in rows on a large platter or in a serving bowl.
In a screw-top jar combine the Strawberry Vinegar and salad oil. Cover and shake well. Drizzle over salad. Store any remaining dressing in the refrigerator. Makes 8 to 10 side-dish servings.
In a medium stainless-steel saucepan combine strawberries and vinegar. Bring to boiling; reduce heat. Simmer, uncovered, for 3 minutes. Remove from heat. Pour the vinegar-berry mixture through a fine-mesh strainer; let liquid drain into a bowl. Discard the berries. Transfer vinegar to a jar or bottle. Cover tightly with a nonmetallic lid (or cover with plastic wrap and tightly seal with a metal lid). Chill for at least 1 hour. Store in the refrigerator up to 6 months. Makes 1-1/4 cups.