PHNOM PENH—Thuch Sek’s skin is an ink-filled canvas, his Cambodian heritage and American life woven across his back and down his limbs. thug life marks his right forearm; a misspelled tattoo extolling khemer prideblankets his muscled shoulder blades. The 39-year-old was born in a Thai refugee camp to parents fleeing the Khmer Rouge, the brutal regime that in the late 1970s killed nearly a quarter of Cambodia’s population; at the age of 2, he resettled with his family in Philadelphia.