THE two newest additions to the stock exchange - Wanon International and New Island Printing - hit the market with a flourish yesterday. Wanon, which makes cordless telephones, was the third most heavily traded issues with a volume of 30.34 million units. The shares, issued at $1, quickly climbed to $1.37 before ending the day at $1.14. Wanon's 1996 warrants closed at 53 cents after trading between 50 and 68 cents. New Island, which is involved in the printing and manufacturing of packaging products, books and brochures, had a turnover of 21.27 million shares. The shares, also issued at $1, peaked early in the day at $1.28 before slipping to $1.11 by the close of trading.