Make the pesto. Preheat your oven to 400°F. Line a rimmed sheet pan with aluminum foil. Arrange the tomatoes in a single layer, add 1 tablespoon of the olive oil, and move them around with your hands to coat the tomatoes. Roast for 20 minutes, then set aside to cool.
While the tomatoes roast, toast your almonds. Add them to a small skillet over low heat and cook, tossing often (so they toast evenly) for about 5 minutes.
Add the toasted almonds and the garlic to a food processor and pulse until finely ground. Add the cooled roasted tomatoes, basil, Parmesan, and salt. Pulse well to combine, using a spatula on the sides of the food processor (this can be on the chunkier side if you prefer but I like mine pretty smooth). Drizzle the olive oil through the shoot while the processor is running until the mixture is emulsified and smooth.
Bring a large pot of generously salted water to a boil and cook the rigatoni according to package instructions until al dente. Drain and add to a large serving bowl.
While the pasta is cooking, toast your breadcrumbs. Heat a medium skillet over medium-low heat then add the olive oil and garlic and cook for 30 seconds or until fragrant. Stir in the Panko, red pepper flakes, and salt, tossing until there are no dry bits of Panko. Cook, stirring frequently until the breadcrumbs are evenly golden brown and fragrant (about 5 minutes), taking care that nothing burns. Remove from heat and grate the lemon zest into the breadcrumb mixture.
Add 1 ½ cups of the pesto with the pasta and toss well to combine. Add the mozzarella pearls and toss again. Divide between 4 serving bowls and top each portion with more fresh lemon zest, basil, red pepper flakes, and 1 tablespoon of Panko breadcrumbs (or more, if you like).
