In a food processor, puree the butter, tomatoes and garlic until it forms a smooth paste. Heat a small saute pan over medium heat and add the butter mixture. Heat the butter until melted down and fragrant, about 3 minutes. Keep warm.
Heat a large saucepan over high heat. Once hot, add the popcorn kernels and oil, and shake the pan to coat the kernels in the oil. Cover and continue to cook over high heat until the kernels begin to pop. Shake the pan once again and reduce the heat to medium-high. Continue to cook until the popping slows dramatically, 1 to 2 minutes.
Pour the popped popcorn into a large bowl. While still warm, add the flavored butter, cheese, oregano and salt. Toss to coat, and then serve.