Pulse 4 garlic cloves, two 15-oz. cans chickpeas, rinsed, ⅓ cup tahini, ¼ cup fresh lemon juice, and 2 tsp. Diamond Crystal or 1¼ tsp. Morton kosher salt in a food processor until combined; season with freshly ground black pepper. With the motor running, stream in ⅓ cup extra-virgin olive oil and ¼ cup water; process until very smooth, about 2 minutes.
Heat ⅓ cup extra-virgin olive oil in a medium skillet over medium-high. Cook two 8-oz. blocks tempeh, crumbled, stirring occasionally, until golden brown and crisp, 6–9 minutes. Add 2 Tbsp. tomato paste, 2 tsp. fennel seeds, 2 tsp. ground cumin, 1½ tsp. smoked paprika, and ½ tsp. cayenne pepper; season generously with salt. Cook, stirring often, until tempeh is coated and tomato paste is slightly darkened, about 2 minutes. Add ¼ cup water and cook, stirring and scraping up any browned bits, 1 minute.
Combine 1 large fennel bulb, halved, cored, thinly sliced, and 1 small red onion, thinly sliced, in a medium bowl. Drizzle with oil and remaining 2 Tbsp. fresh lemon juice and season with salt and black pepper; toss to combine.
Spread hummus in shallow bowls and pile tempeh on top. Arrange fennel salad alongside; top with fennel fronds. Drizzle with oil; season with more black pepper.