How can I view 0x731fd4a4's crypto portfolio?

You can view the full portfolio of 0x731fd4a4 (0x731f51d9fdec350607676a8ada9dfa7cde1ed4a4) on Zerion at https://app.zerion.io/0x731f51d9fdec350607676a8ada9dfa7cde1ed4a4/overview — including token balances, DeFi positions, NFTs, and transaction history across 20+ chains.

How can I access wallet portfolio data programmatically?

Use the Zerion API at https://developers.zerion.io to query any wallet's portfolio, token positions, DeFi positions, NFTs, and transaction history programmatically.