Greetings BuddhaStudent,
To help you understand these responses a little, Theravada Buddhism is based primarily on the Tipitaka. In the Tipitaka, the subject of prayer and wishing in general is as explained by Tiltbillings... it is not through prayer that things are achieved, especially not global peace.
However, if people develop loving-kindness and compassion, then they become more peaceful individuals and better world citizens. They cause less suffering to others and help make the world a better place. If you wish to encourage Theravada Buddhists to make the world a better place, the way is not through encouraging supplication to Buddhas, bodhisattvas, Dhamma protectors or deities. Rather, it is through the cultivation of the brahma-viharas (divine abidings) - namely, metta (lovingkindness), karuna (compassion), upekkha (equanimity) and mudita (appreciative/sympathetic joy)... as well as encouraging good deeds, adherence to precepts, and opportunities for making merit.
Metta,
Retro.
"Whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things."