Cut tops off tomatoes and scoop out the core and flesh with a spoon, being careful not to puncture the skin. Reserve 1/2 cup of tomato flesh in a bowl.
Brush tomatoes with 1 tablespoon olive oil; season with salt and pepper. Arrange tomatoes on a baking sheet.
Bake in the preheated oven until softened, about 6 minutes. Pour out any juices that collected in the tomatoes.
Mix kasha and eggs together in a bowl.
Heat 1 tablespoon olive oil in a large skillet over medium heat. Add onion and 1 clove garlic; cook and stir until onion is translucent, about 5 minutes. Pour in kasha mixture; cook over medium-high heat, stirring constantly, until kernels separate and look dry, 1 to 2 minutes.
Pour vegetable broth into the skillet. Reduce heat; cover and cook until kasha is tender and broth is absorbed, 7 to 10 minutes. Stir in corn, chili powder, cumin, salt, and pepper. Remove from heat and stir in about 1/2 cup Monterey Jack cheese.
Set oven rack about 6 inches from the heat source and preheat the oven's broiler.
Spoon kasha mixture into the tomatoes. Sprinkle remaining 1/2 cup Monterey Jack cheese on top.
Broil tomatoes in the preheated oven until cheese has melted, 2 to 3 minutes.
Combine almonds and toasted bread in a food processor; process until finely ground. Add reserved tomato flesh, roasted red peppers, 2 tablespoons olive oil, sherry vinegar, 1 clove garlic, sea salt, and cayenne pepper; process until smooth. Spoon sauce over tomatoes.